Tank is a robotic frog that is a playable character in Frogger 2: Swampy's Revenge.
Official Bios
Frogger 2: Swampy's Revenge Bio
"No-one knows who built this frogbot, found abandoned deep in the labs, but having been activated he's a loyal member of the team. He positively will not stop until every frog has been rescued." [1]