Crossbones, Malicious Mercenary 

Legendary Creature — Human Mercenary Villain
Deathtouch
Whenever another Villain you control enters, put a +1/+1 counter on Crossbones. He deals 2 damage to each opponent. This ability triggers only once each turn.
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Flying Octobot 83%
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"Whenever another Villain you control enters, put a +1/+1 counter on this creature. This ability triggers only once each turn."