In conversations with people about what animal scares them the most, common answers are things like ‘grizzly bears’ or ‘great white sharks’ or ‘crocodiles’ or ‘lions.’
For me, other than functionally scary things like the Brazilian wandering spider the creature that makes me mentally shit my pants is a big, male chimpanzee.
Nearly as smart as us. Fast. Explosively aggressive and brutally violent under the right conditions. And strong beyond all comprehension. Chimps are not to be fucked with.