Clockwork Swarm is a common Artifact Creature — Insect card from Magic: The Gathering (Masters Edition IV, ME4).
Common
Masters Edition IV (ME4)
{4}
Power / Toughness
0 / 3
Mana Value
4
Card Text
This creature enters with four +1/+0 counters on it.
This creature can't be blocked by Walls.
At end of combat, if this creature attacked or blocked this combat, remove a +1/+0 counter from it.
{X}, {T}: Put up to X +1/+0 counters on this creature. This ability can't cause the total number of +1/+0 counters on this creature to be greater than four. Activate only during your upkeep.
