Erasure, Humble Teacher

{3}{w}{b}, Discard a card: Sacrifice Erasure, then
return up to three student creatures from your graveyard to your hand.
"~sigh~ Based on your reactions I assume the rest of
you were at least aware of their plan. I'm going to set
asside a number of issues and just say this. If it
weren't for All Might's retirement from the hero scene,
I would expel everyone here...You betrayed our trust...
In order to regain our confidence you'll need to...live
as model students."