Wikipedia tells me that the procoptodon was a "genus of giant short-faced kangaroo," the largest of which stood around two metres tall. That makes it tall enough to ride in the world of Ark: Survival Evolved [official site], and the animals have now been added to the game for that purpose - with the twist that it can be ridden by two players simultaneously, and one rests inside the kangaroo's pouch.
As explained in a Steam news post, the kangaroo are the first Ark animal which can carry two players simultaneously. Given the size of some of Ark's dinosaurs, some of which are large enough to act as mobile turret platforms, that's surprising. But the "pouch-bound passenger is able to make fully effective use of all weaponry while riding", says the update. Here's a video introducing the creature:
As demonstrated, the kanga can jump large distances, clearing terrain that might be hard or slow to traverse with other animals. Also the pouch thing is so cute.
Additions to Ark seem to flit between the borderline reasonable and the outright silly, depending on whether it's introducing dinosaurs like the gigantosaurus, quetzalcoatlus and pachycephalosaurus, or crowdpleasing animals like penguins, monkeys and direwolves. The nexus between these two groups is the Sonic-inspired armadillo-dinosaur doedicurus, which can roll into a ball to protect the human riding it. That's going to take some beating.