Xenon Specter

Shadow (This creature can block or be blocked by
only creatures with shadow.)

Whenever Xenon Specter deals combat damage
to a player, that player discards a card at random.
If that card is a land card, exile it instead and add
one mana of any color.
Xenon Specter is the heaviest of the specters, and its
touch can drain the very essence of life.