Dorguy the Third
From the Super Mario Wiki
Dorguy the Third is the last of Queen Jaydes's guardian doors in Super Paper Mario. He is found even deeper than previous doors in the path from The Underwhere to The Overthere. Like the other Dorguys, he must open only to trustworthy people. Unlike his predecessors, he does not ask questions. Instead, he summons the Underchomp, a three headed Chain Chomp creature, who Mario, Bowser and Luigi must fight if they want to pass by him.