Cuttlefish and other cephalopods are well known to use camouflage and mimicry, but these pharaoh cuttlefish change their appearance and behavior to mimic hermit crabs.
It is simply amazing. National Geographic writes that researchers from the University of the Ryukyus, Japan, observed this unusual behavior while feeding the cephalopods in the lab. The researchers believe the cuttlefish pretend to be hermit crabs as a form of defense useful in hunting small fish.