Spreading Moss

Defender
At the beginning of your upkeep, all players create a token copy of Spreading Moss.
At the beginning of your end step, if there are 250 or more creatures named Spreading Moss on the battlefield, exile them all. For each non-token named Spreading Moss exiled this way, its controller creates a 10/10 legendary green Elemental Plant creature token named Mozz with trample.