Crackdown Construct + Crypt Rats

Crackdown Construct

Crypt Rats

How it works

1. Activate Crypt Rats by paying 0.
2. Crackdown Construct triggers, giving itself +1/+1 until end of turn.
3. Repeat.

This ingenious pairing turns a humble rat plague into a towering colossus by exploiting a subtle rules quirk in how activated abilities work. By declaring an X value of zero for Crypt Rats, you can repeatedly activate its ability for no mana cost without actually firing off a lethal blast. Each time you announce that zero-cost activation, Crackdown Construct's static ability notices you are activating an ability of a creature that isn't a mana ability, happily granting it a permanent-until-end-of-turn growth spurt. By looping this zero-mana activation as many times as you desire, you pump Crackdown Construct into an infinitely large threat ready to trample the competition.