bigmouth is an enemy commonly found in ghost houses, mansions, and are mostly found in biggermouth's ghost ship (6-4) when Halloween edition is activated via the secret code screen (code: BOOHOO-CRYBABY). they are normal boos but with eyes similar to shy guy's and a mouth similar to shy guy's, but much bigger. they only appear in super DUPER Mario bros.
- bigmouth is also named loudmouth due to their high-piched squealing similar to the sound a tapir makes, or shy boo\boo guy.
- he is one of the two ghosts that get a boss counterpart. the other being goopa troopa.