Half-life

Whenever an opponent casts a spell, Kaervek deals damage equal to that spell's mana value to any target.

If a source would deal damage to a permanent or player, it deals double that damage to that permanent or player instead.

Equipped creature gets +2/+2 and has infect. (It deals damage to creatures in the form of -1/-1 counters and to players in the form of poison counters.) Whenever this Equipment becomes unattached from a permanent, sacrifice that permanent. Equip