Hitchhiking abalone

[christyf5]

So the lights are off in my tank but I decided to see what I could of my half dead corals with a flashlight and I see a rather large piece of live rock making its way across the tank. Its an abalone that I guess came in on one of my corals or something. I've never seen it before. Quite scary actually. Anyone have any experience with one of these things. Its about 2.5 inches long.

abalone:
http://www3.telus.net/seamonkey68/abalone3.jpg

Christy :)