Lego Undersea Explorer
Another one of the Lego sets that we discovered in our tub-o-Lego was the Underseas Explorer, part of the Atlantis series of Lego models. This one was missing a couple of the wheels (there should be three on each side rather than two) and one of the leg armour modules has been repurposed from Lightning McQueen of Cars fame.
I have no idea what type of ferocious fish this is; it appears to be pretty much all mouth and tail.
The Undersea Explorer is somewhat of a transformer and converts from its mech/robot form into a more traditional ocean bottom crawling mini-sub.