I found it. For some reason it's upside down. It's beside. It's 2 tiles above the F tile in TLP. Above Sprite 0 (The half coin), and beside various pirhanna plant tiles.

It's likely that the squished Goomba tile is upsidedown because most enemies in SMB are displayed inverted after they die. By making the tile inverted to begin with, it avoids another special case, of which the Goomba already has quite a few.