Whenever Slurrk or another creature you control dies, if it had a +1/+1 counter on it, put a +1/+1 counter on each creature you control that has a +1/+1 counter on it.
Partner (You can have two commanders if both have partner.)
Slurrk is a mono-green +1/+1 counter engine that snowballs your whole board: load creatures with counters, then sacrifice or trade them so every counter-bearing creature grows. You build a wide, counter-laden board over a few turns, then crash in for lethal combat damage or overrun the table once your team gets out of hand. Partner lets you pair Slurrk with a second commander to add an outlet, a sac engine, or another color.
Comes online immediately with five counters and turns every creature death into a board-wide pump
Mono-green gives access to the deepest counter-synergy and ramp packages in the format
Partner adds flexibility to splash a color or grab a sacrifice/aristocrats payoff
Resilient to single-target removal since the value is spread across many creatures
Rewards aggressive trading in combat that other decks find awkward
Board wipes are devastating since the whole strategy is creature-based
Mono-green struggles with interaction, card draw outside of creatures, and removing problem permanents
Slurrk's trigger needs creatures to die, so you can stall without a sac outlet
High mana value (6) and reliance on the commander make recasting costly
No evasion built in—gets chump-blocked or stonewalled by go-wide defense
Banks counters from dying creatures so your investment is never wasted.
Add counter doublers (Hardened Scales, Branching Evolution, Doubling Season) and free sac outlets (Ashnod's Altar, Goblin Bombardment) to make the death trigger fire repeatedly and explosively. Choose a Partner that supplies what mono-green lacks—an aristocrats payoff, removal, or a sacrifice engine—and tighten ramp with fast mana like Sol Ring and mana dorks. Top-end finishers (Craterhoof, Pathbreaker Ibex) plus protection like Heroic Intervention guard against the board wipes that otherwise undo the whole plan.