Caltrop Bots

Caltrop Bots enters the battlefield with x spike counters on it. Whenever a creature an enemy controls attacks remove a spike counter and attach it to attacking creatures. Creatures with spike counters gain cumulative upkeep 2. When a creature with a spike counter dies gain life equal to the cumulative upkeep cost paid. Sacrifice Caltrop Bots if there are no spike counter on it.