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.

The Undersea Explorer is somewhat of a transformer and converts from its mech/robot form into a more traditional ocean bottom crawling mini-sub.