Try a rubber worm. actually they are an amphibian, but I have been keeping one for 3 years. I think it is about as odd as you will find. Mine is very peaceful and lives in my planted 125g discus tank.
This is a cool oddball and they only cost like 15 bucks... They are allways stressed. They will adapt to you and eventually come out to see you during the day... They are mostly active at night.