Placodus ("flat tooth") is a genus of placodont from the Middle Triassic of Europe and China. It probably behaved similarly to a modern day marine iguana, living on both the land and the water. It ate clams and other shellfish, using its chisel-like incisor teeth to scoop up shells. Like a modern day tuatara, it had a "third eye" on the top of its head. However, this "eye" was used for orientation, not sight. It had strong body armor, which it used to protect itself from predators.
In The Land Before Time
Placodus appears as an enemy in The Land Before Time for the Gameboy Advance. It appears in both blue and green variations. Both variations are seen in the second area of the game, Smelly Swamp, while the blue variations also appear in the game's fourth area, Dark Cavern. They are strangely seen far away from their normal ocean environment, though this may be due to the fact that the species was amphibious and could crawl onto land if need be. They walk back and forth until they collide with the player. However, they can be simply defeated by jumping on their back. Both variations give the player 50 points when defeated.