Mischief
Gremlin
A mischievous creature or being, often attributed to causing problems
Hairy Houndini
A playful reference to a dog with a lot of hair and a magician, inspired by Houdini
Joker
A person who jokes or plays pranks
Mex
A playful and upbeat term, often associated with Mexican culture.
Rascal
A mischievous or cheeky person
Scalawag
A scamp or rascal