These are what we call the 'YMMV items.' Things that some people find in this work. We call them 'your mileage might vary' because not everyone sees these things in the same way. This starts discussions in the trope lists, a thing we don't want. Please use the discussion page if you'd like to discuss any of these items.
Demonic Spiders: Lions. They hit like trains, they come in large quantities, they're frequently everywhere, they take a lot of effort to kill, and they can frequently call for help typically having 3 or 4 arriving at once. Only a handful of high end animals can ever hope to take them on in a stright on fight... and they're no more rewarding to kill then any other animal.
Dilophosaurus as well bordering on Boss in Mook Clothing. While not nearly as durable as a lion they are much faster, hit harder, and are utterly relentless in their attacks.
Player Punch: During Act 3 (the Sika Deer's chapter), the deer and its sibling encounter a cheetah. You are then given a tutorial popup telling you that you should use your defensive ability. Said popup simply shows a picture of a Killer Rabbit sporting a Death Glare, so you might think that this defensive ability is going to be some totally badass maneuver that'll save you from that horrible cheetah, right? Your defensive ability is to abandon your sibling and let the cheetah have them while you make a getaway. It's either depressing or downright hilarious depending on your point of view.
Herbivores. At least early on. You're usually too weak to kill anything, and it wouldn't help you survive even if you did, since you can only eat plants.
That One Level: Act 7 of the story mode. You're playing as a lion and have to defend your pride against some nomad lions and hyenas who want to take it over. What makes it frustrating is that you have to defend your lion cubs as well; if they all die, you automatically lose. The cubs will attack any enemy that gets near and won't get out of the way of enemy attacks. However, if you stray too far, you obviously leave everyone open for attack. It almost feels like the game is deciding whether you'll complete the mission at times.
Unlocking the lion in survival mode. The mission is a standard take over, but the area in question gets flooded with dozens upon dozens of lions each one more then a match for the tiger. Your best bet is having a full pack and simply ignoring the lions altogether, hoping to cap the points before they kill you.