The Firewall Sentry

Begin the game with this card revealed.
When a noncreature spell is cast, its controller
takes 2 damage.
When a creature spell is cast, its controller
discards a card.
When a creature attacks, its controller takes
2 damage for each attacking creature.
When a creature would increase a player's life
with lifelink, its controller loses life instead.
Creatures that attack, lose deathtouch, first strike
and double-strike, trample, and takes 3 damage.