The Merchant

Whenever a creature card enters your graveyard
from your library, each player creates a 1/1 Black
Worm creature token. Whenever a land card
enters your graveyard from your library, each
player creates a treasure token. Whenever a
noncreature, nonland card enters your
graveyard from your library, each player draws
a card. These effects occur only once each turn.
"What're you buying?"
--- The Merchant