So... I've been playing a Norn Engineer on GW2, having fun burning things with my flamethrower, and later smashing them with a wrench from my tool kit:
One of the abilities in my tool kit is a box of nails to throw everywhere and cause bleeding:
Fair enough, a box of nails makes sense as something in a toolkit.... however, upon entering the water, this ability (like many others) changes to an aquatic version:

Wait what?

Where did I even get a hold of piranhas? Let alone think of keeping them in a box as a part of a "tool" kit?