The Japanese Giant Hornet-Got it from my friend el Gato.

Japanese Giant Hornet (vespa mandarinia japonica)

From: Japan, obviously.

Why you must fear it:
It's the size of your thumb and it can spray flesh-melting poison. We really wish we were making that up for, you know, dramatic effect because goddamn, what a terrible thing a three-inch acid-shooting hornet would be, you know? Oh, hey, did we mention it shoots it into your eyes? Or that the poison also has a pheromone cocktail in it that'll call every hornet in the hive to come over and sting you until you are no longer alive?

Think you can outrun it? It can fly 50 miles in a day. It'd be nice to say something reassuring at this point, like "Don't worry, they only live on top of really tall mountains where nobody wants to live," but no, they live all over the goddamned place, including outside Tokyo.

Forty people die like that every year, each of them horribly.

More scary shit:
Here's how the Japanese hornet treats other insects (and would presumably treat us, if we were small enough). An adult hornet will fly miles to find some squishy shit to feed to its children. Often times, it finds its food in, say, a hive inhabited by thousands of bees.

What to do? Well, Vespa japonica sprays the nest with some of the acid/pheromone and brings in reinforcements, usually consisting of 30 or so fellow hornets. They then descend upon the beehive like an unholy plague of hell-born death engines and proceed to make this world a scary goddamned place. This is maybe 30 wasps against 30,000 bees and the 30,000 bees do not stand a chance.