Hawkmouths are eagle-head gates found in Super Mario Bros. 2. They are stationed at the end of each level, attached to walls. Entering a Hawkmouth transports the player to the next level, or into the room of the current world's boss. To open a Hawkmouth, the player must pick up a Crystal Ball, which is either placed out in the open or must be surrendered from an attacking Birdo.
All Hawkmouths are harmless to the player, except for one, which is stationed in Wart's Castle. The Hawkmouth here detaches itself from the wall, and begins to chase the player in a manner similar to a Phanto. The player must attack using the Mushroom Blocks in the vicinity to temporarily stun the Hawkmouth to provide entry into Wart's throne room. However, if the player doesn't enter into the Hawkmouth when it's stunned, it'll eventually reanimate itself again.
What appears to be a Hawkmouth appeared in the episode "Too Hot to Handle" of The Super Mario Bros. Super Show!. Although King Koopa leaped into the Hawkmouth at the climax of the episode to make his getaway, it appeared to be inanimate and was made of stone.