Mami, The Creator

Trample
When Mami, The Creator enters the battlefield,
all children on the battlefield enter your possession.
All children have a mana cost of {0} .
At the end of turn, put a tired counter on Mami,
The Creator for each child in play.
During your upkeep, if Mami, The Creator has 25
or more tired counters, exile Mami, The Creator.