Osterhases (sometimes called Wallahases in Australia) are Easter hares or rabbits that were said to hatch and hide in multicolored eggs for children. But also the osterhases can even hold and hide their multicolored eggs on their wallaby-like pounches, hence their name.
If a multicolored egg has hatched, then the baby osterhase is called a babyhase, the babyhases have also their joey-like pouches on their belly.