Mei, Glacial Climatologist

Defender, protection from white
Whenever Mei, Glacial Climatologist enters
the battlefield put X 0/2 blue Wall creature
tokens with defender onto the battlefield.
Whenever a creature becomes blocked by
Mei, Glacial Climatologist that creature
taps and does not untap during its controller's
untap step for as long as you control
Mei, Glacial Climatologist.