Zhim'Daal, The Grim Watcher

Zhim'Daal, The Grim Watcher enters the battlefield under target opponents control.
At the beginning of your end step, create two 1/1
Green Saporling tokens with: "At the beginning
of your upkeep, lose 1 life."
Zhim'Daal, The Grim Watcher's controller may sacrifice a nongreen creature during their upkeep
to have target player gain control of Zhim'Daal,
The Grim Watcher.