Behold, the Cyphonia clavata, otherwise known as the ant-mimicking treehopper.
Which, incidentally, is awfully fun to say.
What you are seeing is an insect that has evolved to look like an ant walking backwards. The treehopper’s eyes can be seen on the left of the picture, so to a predator it looks like the advancing treehopper is a retreating ant.
Being a gamer and prone to grisly ideas, when I first saw the image I thought the treehopper would kill an ant and wear its corpse as a shell, much like the disguised Mi-Go in H.P. Lovecraft’s The Whisperer in Darkness, but the reality is even more cool. The treehopper has evolved so that the same mechanisms that grow its wings create this amazing piece of camouflage, allowing it to grow the helmet-like ant mask as part of its natural body.
Science fiction and fantasy games are full of insect-based life forms, such as the Thri-kreen of Dungeons & Dragons or the Vrusk of Star Frontiers. Imagine the discomfort your players will have when they encounter a friendly race of insect people who grow shells that make them look vaguely human. Beings who believe that wearing this grotesque parody of our species is a tribute to us, a sign of friendship.
Then as soon as the characters become comfortable with this bizarre practice, have them encounter one of these creatures whose carapace vaguely resembles someone they know. Someone they haven’t seen for a while.