Bootler is a character in Paper Mario for the Nintendo 64. He is an elderly Boo with a mustache. When he was younger, he used to adventure with Goompa and Koopa Koot. When you first meet up with him in the game, he'll be working for Bow in Boo's Mansion. When Bow agrees to venture with Mario to defeat Tubba Blubba, Bootler wishes that she wouldn't do so, and even suggests that he goes along with them in case something goes terribly wrong, though she ends up denying this and goes alone with Mario and crew.
Bootler is a master at scaring almost anyone, especially the nervous ones such as Fice T., who despite his name is the exact opposite of being "feisty". Bootler seems to have an interest in scaring Fice T. He even manages to frighten Mario.
In the entire Mario series, Bootler is the only Boo with facial hair, excluding some of the Boo Portraits found in the same game.