The animal of the day is the Lamprey. (Did you know:Ugh. I can barely look at that picture above without getting the heeby jeebies!
Lampreys die right after they lay eggs (thank god), and they come in both freshwater and saltwater varieties. They feed by sucking the blood from live fish. These parasitic assholes made their way into the Great Lakes in the early 20th century and have been a pain in the local ecosystem ever since.