In "The Legend of Grimace Island", it's rather fitting that Birdie, an anthropomorphic bird, occupies the crow's nest during the McDonaldland gang's boat trip.
Some of the villains' actions are perfect contrasts to the behavior of the McDonaldland gang. Professor Pinchworm takes advantage of Hamburglar's guilt at not getting Ronald a birthday present in time so he can lure everyone into his trap, but Ronald makes it clear in the end that he holds no hard feelings for Hamburglar being manipulated by Pinchworm (and likely wouldn't have taken it personally had Hamburglar showed up at the party without a present anyway). One-Eyed Sally and Stiles, meanwhile, are frequently hard on their henchmen Blather and Pip for their idiocy, but Ronald and friends never give Grimace any grief for when he causes problems out of stupidity and are patient enough to steer him in the right direction when needed.
While his fate was arguably karmic, it's disturbing to think that Pinchworm quite potentially got eaten by his mechanical dog. Especially since he had been transformed into a toddler.
Pinchworm's plot in general was full of this. As noted on the main page, his plan was to turn everyone in the world but himself into babies, which could have quite easily led to humanity's extinction due to the inability of everyone to take care of themselves.
We don't know if Ronald and friends were the first people Pinchworm tested his Babe-O-Matic Ray on, and given how prepared he is to use a larger scale model to change everyone on the planet into babies, one has to wonder how many models of the Babe-O-Matic Ray Pinchworm went through to perfect the process, how many people he duped into being his guinea pigs before he came across Hamburglar moping about forgetting to get a present for Ronald's birthday and what kind of nasty side effects Pinchworm had to work out before he made the model tested on the McDonaldland gang.
Since Ronald and the others weren't returned to their normal ages until Pinchworm's ray was destroyed and we last saw Pinchworm turned into a toddler by his own ray with no apparent way to reverse the process, it's not clear whether those affected by Pinchworm's Babe-O-Matic Ray would've eventually grown back to their proper ages given time or if they'd be stuck as infants forever.
What would happen if the Babe-O-Matic Ray was used on someone who was already an infant?
King Murray sends Ronald and friends to the dungeon in "Have Time, Will Travel" just because they caused him to be laughed at while in his underwear. With the knowledge of certain aspects of the medieval era that wouldn't normally be addressed in media aimed at children, one has to wonder if King Murray ever went further and sentenced a person who slighted him to death for anything equally as trivial.
The prehistoric counterparts to the McDonaldland gang wave goodbye to their descendants as they get inside the burger Ronald inflated so they could get inside the Tyrannosaurus Rex that ate Dr. Quizzical's time machine. Since the prehistoric McDonaldland gang weren't informed about the plan aside from Ronald deterring his caveman counterpart from eating the burger they enlarge to sneak inside, it comes off as them not doing anything as they watch Ronald, Grimace, Hamburglar, Sundae, Birdie and Franklin seemingly commit suicide by letting a dinosaur eat them.
King Murray's royal chef wanting to cook Birdie in spite of her clearly being a sentient being suggests that Fantastic Racism was prevalent during the middle ages. Heck, it isn't clarified if the blackbirds the chef wanted for the pie and the knights failed to catch were ordinary blackbirds or were sapient like Birdie.
It isn't stated what the angry mob who mistook Hamburglar for his Wild West ancestor intended to do once they caught him, which leaves open the disturbing possibility that Hamburglar could've been subjected to hanging had the gang not been able to time-warp out in time. Heck, depending on whether this part takes place when Hamburglar's ancestor has started a family, it's possible that had the mob caught the actual Henry H. Burglar II, they would've gone through with executing him with no regard to how his death would have effected his wife and child(ren).
