Infographic Riddle. What animal lathers its body in fertiliser to attract plants?

– king of camouflage
– looks like a stone
– makes anti-foulant
– expandable mouth
– swallows prey alive
– has gills
– but NO scales
– sheds it’s skin
– but it’s NOT a snake
– never smiles

The animation was used in the following video by The Nature of Science:

Motion graphics design by Vlad Dimov – http://www.vladdimov.com