Just part of the allure of the opposum!!
It is green colored mucus. Sort of a protective mechanism against attack from predators.
"Opossums are known for playing dead when predators are nearby or attack. The opossum is so good at it that it could win a creepy contest when it falls on its side, becomes limp and motionless, while the front feet ball up. Drool then comes out of its mouth and it poops with some extra green smelly mucus. Who would want to stick around this scene?"
http://dnr.wi.gov/org/caer/ce/eek/critter/mammal/opossum.htm Originally posted by bean:
...what is the green ooze that comes out of a grinners butt? Don't think it is scat. Seems like most of ours have that. Pretty nasty.