This year I made a banana slug costume to wear during our Halloween storytime session at the library (I'm a children's librarian). I've had bad luck with relatively mild costumes scaring children in the past (think lamb, bunny, lobster with winter mittens), but I've discovered that kids respond well to yellow.
Apparently, so does my cockatiel.
Thanks for looking!
Please forgive my I-stayed-up-all-night-to-make-this face.