* Burt has the head of the Graboid he killed in the first movie stuffed and mounted on his wall in the second. The Graboid that he and his wife killed by shooting it in the head for 2 minutes. Shouldn't it's head be in terrible shape?
** It probably was quite messed up but a good taxidermist can piece together a nice trophy even from a horrifically damaged head, a common occurrence in the 19th century when hunting really big game since a head shot is safer than trying to hit the heart of a cape buffalo or rhino charging your ass. Its likely Burt paid for the very best considering it was the first Graboid he ever killed, and for all he knew, the last he ever would (which is accurate to an extent; even after two more movies and a series, he never killed another Graboid that actually ''had'' a head left to preserve).
*** Most of the damage Burt and his wife did to the Graboid was inside its mouth, anyway, where it wouldn't have affected the outer appearance as much. The only problem is that the Graboid's tongue-tendrils were effectively obliterated. But even this isn't a huge problem... there were several other Graboids that Burt was involved with killing to some extent. He may have been able to salvage the tongues out of the Graboid that dropped off a cliff, since that was probably all that ''could'' be salvaged. It'd make it a bit of a frankentrophy, but hey, better than being incomplete.
*** Salvaging the tendrils from the worm that fell from the cliff wouldn't work, though. That worm was "Stumpy", the one that lost a tendril trying to grab onto Val and Earl's truck early in the movie.
*** Actually the vast majority of the bullets struck the Graboid's "beak"... probably why it took so long to kill it, since they didn't do all that much soft tissue damage until the very end. And since the beak is already pock-marked and rough from hitting rocks while tunneling, the taxidermist probably just filled and buffed the worst of the bullet holes. The rest wouldn't have been noticeable.
** Better question: what was the Taxidemist's reaction when he was given the chewed-up head of a giant sandworm to make into a serviceable trophy?
*** Who's to say Burt didn't do it himself? Given his extensive study of survival skills, taxidermy might have been among the ones he studied. Heck, a trophy like that might be worth learning the skill for on its own.
*** Even if he did have a taxidermist do it, there's nothing to suggest that the existence of Graboids was kept a secret. Hell, any taxidermist would probably jump at the chance to work on such a creature after reading about in the paper.
** Come to think of it, it may not even ''be'' the actual head of a Graboid, but a plastic replica cast from the remains. The carcasses of all the dead Graboids would be worth far too much as scientific specimens to waste their actual tissues on a trophy, and if they're mollusks as supplemental material suggests, they'd be virtually impossible to preserve that way. (Museums keep mollusks either pressed, freeze-dried or in jars.)
*** But it's no ordinary mollusk, and perhaps a Graboid carcass can last longer.

* In the series all the scientists get worked up about dead skin cells and the like that lie on the bottom of the cave's floor when Mixmaster appears. However nobody seems that concerned over the fact you had a massive mutant wondering around outside the valley that was not only shredding small skin cells but massive hunks of it's shell. It's just woo, we caught the beast and the world is saved.
** And it's stated that Mixmaster was in the water that was brought into Melvin's "lagoon". How many plants, insects, and birds made use of that water before the contamination was discovered. Containing the Mixmaster problem to Perfection Valley is a moot point, although probably great for Burt's survivalist training and monster hunting fees.

* Why did Burt refer to the Graboids as "pre-Cambrian life forms" at the end of the second film? He didn't arrive until ''after'' the conversation in which the geologist identified the fossil as a Graboid-spike, and the creatures' ancient origins never came up as a topic of discussion again.
** Burt may be a CrazySurvivalist, but I doubt he ''quite'' knows palaeontology. And, according to the Sci-Fi Channel, the Graboids and their ilk originate in the ''Devonian'', not the Precambrian; there was certainly terrestrial organisms by the end of the Devonian large enough to sustain the Graboids, but there were only microorganisms during the Precambrian. So in all likelyhood, they're post-Cambrian creatures; beyond that is the realm of speculation.
*** Being found in Precambrian rock in itself would not be a clue to their age, the way it would be for other more conventional species. they dig through dirt and soft rock after all, and a lot of Cambrian rock is fairly soft sandstone or slate. so the fossil that was found could well have been an animal from a much later period tunneling through, and getting trapped and dying.
** Grady mentions "Precambrian life forms" when they're arguing about how they weren't prepared for Shriekers. Though they usually cut that scene short on TV showings for time.

* In the original film, what happened to the body of Edgar, the power-company lineman whom Val and Earl found dead of thirst? They brought his remains to the doctor who confirmed the cause of death, but don't seem to have brought the corpse along when they moved on. The doctor couldn't have dropped the body off in Bixby, as the road got blocked and his vehicle wasn't suited to cross-country driving. If Edgar's body had been at the doctor's camp/building site, he and his wife seem awfully casual about it: a body in the desert heat isn't exactly going to be conducive to pleasant conversation, and leaving it far enough from their camp to not stink up the place would have been an invitation to coyotes. And it can't have vanished because one of the graboids ate it, because they can only detect moving prey.
** perhaps it was in the station wagon - and was buried when the graboids sucked the station wagon into the ground.
*** So the doc and his wife were cool with having their station wagon smell like a corpse?
** Or after Val and Earl dropped off the body with the Doctor, he and his wife drove into Bixby and turned it over to the authorities or they contacted them and they picked up the body?
*** Then how did they get back to their place again in time to get eaten? Even if they'd made it past where the road crew guys were working before the rocks blocked the route ''to'' Bixby, they couldn't have ''returned'' that way.

* Burt Gummer is a survivalist, meaning that he'd know all about surviving off the grid. That would include communications. So, why didn't he have a HAM Radio? If he did, he and Heather would've been able to make contact with the outside for help. Heck, it would've made perfect sense for Walter Chang to have one given that he seems to be the go-to guy for supplies, ammo and his store is the town's center.
** Handwaved away in one of the films by saying the mountain range blocks such signals so the only ones they can talk to is each other. Which I believe they do in the first film too.
** Radios are exactly what Burt and the folks trapped at Walter's place use to talk to each other during the first film's siege. Probably they ''could'' have used those to contact outside help under normal circumstances, but in this case everyone who was closer to Bixby - hence, wouldn't have as many mountains between them and that town - and could relay a message out of the valley, had already been killed.

* Why would the federal agents be so adamant about protecting the graboids? They eat anything that moves or has body heat, making them a threat to everything else in the ecosystem. There is also the fact that they are prehistoric holdovers which means they are an invasive species in the modern day.
** They are also a rare species, and as such would be protected by the Endangered Species Act. and being prehistoric holdovers does not make them an invasive species. (quite the opposite, really) They'd be allowed to take reasonable precautions to prevent their spread, but genocidal purges against the species would not be legal.
** I'll have to disagree with you on them not being invasive, they devour any living thing they come across and no modern animal has any natural defense against them, this makes them a non-native species on a temporal level rather than a regional one.
** Not really. They're as "native" to the modern day as any other ancient species that has survived. They're just incredibly rare and apparently have extremely long gestation cycles before they hatch from their eggs. This isn't a species that was rendered extinct and then brought back by genetic engineering or opening an isolated biome, they're existing in the world as they always have. That makes them a natural species with an ecological niche, and thus worthy of a protected status. They are "invasive" only insofar as their periodic activity to reproduce and spread disrupts human habitation in the same area. Wolf packs are similarly disruptive to farmers and ranchers in their areas, that doesn't mean its open season on all wolves.
** Most of the references to Graboids killing animals near Perfection involve cattle, sheep, horses or burros, none of which are native to the Americas either. Aside from one coyote that was cut off in mid-howl in the second film, I'm not sure if ''any'' New World wildlife was harmed by the species.
** It stated in 3 that the shriekers where multiplying by eating coyotes, lizards and snakes. Additionally, it's ridiculous to think that they don't target native New World species just because they aren't focused on. Especially when it's established that pretty much all stages of the graboid life cycle will indiscriminately eat anything they can detect.

* In the second film, when Burt and Grady found the ailing Graboid dead, with huge hunks missing from its body, why didn't they initially assume it was ''another Graboid'' that attacked it? Burt poo-poos the idea that anything could eat that much in two minutes, but a Graboid could probably munch a huge hunk of meat off a hapless fellow-Graboid in two ''seconds''.
** Most probably, they went by what was known graboid behavior. Graboids are ambush predators that prefer to come up directly under their prey and wouldn't expose themselves by climbing on a rock. In fact, they found the graboid in distress on the rock pretty damn unusual in the first place.
*** Emerging onto the surface to ''avoid another Graboid'' would be a pretty plausible reason for it to have surfaced, though. And so little is known about the creatures' behavior at that point, there's no way to definitively say that they ''don't'' fight one another on occasion.
** There's also the fact their seismo-monitor didn't show any indication of any other Graboids in the area, which would've been beeping up a storm.

* In the first film, when everybody gets on the roof, Melvin is on the roof of a goddamn side-storage hut (or whatever it is). The "building" probably doesn't even have a foundation to begin with, and is made of thin trapeze sheets of metal. Graboids perform just about a ten second attack on it (and pretty vicious one, as you can see they tear a few sheets apart) and then immediately leave Melvin be for the rest of the second act of the movie. Graboids will be shown next to try to tear down the store and Nancy's house. They successfully trip over Nestor's van. But what is going on with the miraculous shed that Melvin resides on? One may argue that they "might" have forgotten about the shed, BUT then I remembered Rhonda saying that the rocks are very good conductors of sounds and vibrations. Well, guess what is even better conductor? Yes, metals. Even if Melvin didn't do anything more than lie on the roof and breathe, it would still be enough for graboids to focus their mind on it. But he was actively shouting while on it, stomping, cheering, and whatnot.
** In addition to the question, but about inverted situation. Burt's jeep is certainly NOT making any sound before graboid attacks it. Sure the alarm went off, but that was after graboid started drowning it. Why did the graboid target the car unless the graboids are more intelligent than they're letting people know? But that goes in contrast to the original question. Melvin should have logically been between the victims in the movie. Graboids did not benefit in any way leaving him alone.
*** The Gummers' vehicle was disturbed and its alarm went off because the Graboid circling their place was shifting the gravel underneath it. There's an angled shot showing how the pavers and gravel were rising and falling with its passage. It wasn't doing anything different from what the other Graboids were doing, up to then: investigating the foundations of the buildings.

* How is it possible for there to even be a Mindy rescue scene from pogo-stick? Why weren't everyone to the last citizen of Perfection gathered to Chang's market at once? Val, Earl and Rhonda have ALL the info on graboids, yet behave like it's no big deal when they return to the town. A deleted scene even shows their arrival and they just say something like "Yeah, let's go at Walter shop, but whatever...". They know how dangerous graboids are at this point, they know they're bigger than just the snake tongues, they know graboids are heading towards Perfection, and they know they hunt by sensing vibrations. Then we have a scene where the people ''start'' looking for Mindy. And at this time she is f-cking POGO-STICKING around the place! Emitting more vibrations than anyone else walking or standing. Even if there hadn't been giant worms, the people were at least suspecting murdering snakes! And Nancy STILL let Mindy play outside, let alone in the open ON a pogo stick WITH headphones on. There's some IdiotBall from everybody in the first town attack. Let alone that Mindy was pogoing all the time. She should have disappeared in the fashion of Pipit, the dog from Jaws. Nobody was overseeing her and she attracted predators. But I guess [[EvenEvilHasStandards graboids]] [[WouldntHurtAChild are choosing their prey]], judging by the previous headscratcher.
** The characters don't catch on that the Graboids are actually moving towards the town until they start to compare notes and check maps ''at'' Walter's store. It's not until Val catches on that the creatures aren't just roaming at random around umpteen miles of desert and badlands that they realize threat is imminent.

* Other than making the scene intense, why would Burt ask Heather what rifle should they bring along? Couldn't they just toss EVERYTHING they have on the roof on the trailer? Just by arguing what to toss to others, they are wasting precious time. Had they started throwing everything, they might decide later what gun to use and what not. It's not that the trailer cares if it carries a few more guns. A simple scenario of "catch" and "got it" could be more fruitful. The more firepower, the better chance at graboids, as Burt and Heather have got to know by their own experience. Even if they don't get the chance to use all the guns, it's better to have more, than none.