If you have a cat or bird or reptile or large insect even a hamster,
ect, then take cloth and wrap it around it's neck put any superhero design you want on it for it's costume.
For pets with tanks ( fish, ants, insects, and or reptiles, ect) cut out halloween
decorations and tape them onto the tank instead.
May work for cages too.
You can even make your own Halloween themed pet treats just don't use real candy.
Remeber not to let any pets out or pet any pet you see while trick or treating it could
be dangerous.