Jurassic Park: Dominion - Now With More Eating People

[VoxRationis]

As far as invasiveness goes, I think Movie!Compsagnathus would probably be the biggest threat, as far as all the dinosaurs we've seen go. Small, fast, carnivorous, travel in groups, and capable of bringing down prey much larger than their individual body masses, these things would be a problem if a breeding population ever got themselves established in a vaguely wild area.

Maybe that's the point, though! I kind of want the antagonists to end up being a group who judge that we've just wasted all our chances at averting catastrophic global warming and so are trying to clone a biosphere from a warmer period. The heroes track them down to their lab and see vast cloning facilities churning out all the boring flora and fauna that InGen found DNA for but didn't think were worth cloning just for the sake of better decor in their theme park. They're just shotgunning species out into various places and seeing what sticks, hoping either there will develop ecosystems that humans can use to support society or that just something survives that's not jellyfish.

*Though truth be told, I think the compies don't really make sense as presented. We see (in Lost World) that they can overwhelm even adult male humans through numbers and viciousness, and in III, the stranded kid sees them and immediately recognizes them as a danger, implying that he's probably seen them successfully kill a dinosaur at least of similar size to him, but they're just so small and fragile that the actual mechanics of how that's supposed to happen don't quite follow. The creek scene in Lost World, where the mercenary is lying down and all the compies swarm him, is probably the best-case scenario as far as the compies' attack plan is concerned, but their mouths are so small that it would be difficult to inflict serious (rather than merely painful and annoying) damage, and all the mercenary would really have had to do was roll around as though he were trying to put out a fire in order to either kill his assailants or force them into a retreat.