First printed in Mirrodin Besieged (2011)
Core Prowler 
Artifact Creature — Phyrexian Horror
Infect (This creature deals damage to creatures in the form of -1/-1 counters and to players in the form of poison counters.)
When this creature dies, proliferate. (Choose any number of permanents and/or players, then give each another counter of each kind already there.)
Combos
5 combos from Commander Spellbook, the most popular first.
- Infinite blinking, Infinite colorless mana…: Ashnod's Altar + Core Prowler + Myojin of Grim Betrayal
- Infinite blinking, Infinite colored mana…: Core Prowler + Myojin of Grim Betrayal + Phyrexian Altar
- Infinite death triggers, Infinite creature ETB…: Ashnod's Altar + Core Prowler + Nim Deathmantle + Venser, Corpse Puppet
- Infinite creature ETB, Infinite creature LTB…: Ashnod's Altar + Bog Initiate + Core Prowler + Hex Parasite + The Eldest Reborn
- Infinite death triggers, Infinite creature ETB…: Core Prowler + Krark-Clan Ironworks + Nim Deathmantle + Venser, Corpse Puppet
Legality
Constructed
- Standard Not legal
- Pioneer Not legal
- Modern Legal
- Legacy Legal
- Vintage Legal
- Pauper Not legal
- Future Standard Not legal
- Historic Not legal
- Timeless Not legal
- Alchemy Not legal
- Penny Dreadful Not legal
- Premodern Not legal
- Old School 93/94 Not legal
Singleton
- Gladiator Not legal
Commander formats
- Commander Legal
- Duel Commander Legal
- Pauper Commander Not legal
- PreDH Legal
- Tiny Leaders Not legal
- Oathbreaker Legal
- Brawl Not legal
- Standard Brawl Not legal
- Competitive Brawl Not legal