Roalesk, Apex Hybrid

Mana cost: {2}{G}{G}{U}
Type: Legendary Creature — Human Mutant
Power / toughness: 4 / 5
Set: War of the Spark #213 (mythic)
Price: $0.45 USD

Flying, trample
When Roalesk enters, put two +1/+1 counters on another target creature you control.
When Roalesk dies, proliferate, then proliferate again. (Choose any number of permanents and/or players, then give each another counter of each kind already there. Then do it again.)

Roalesk, Apex Hybrid has 3 printings, first in War of the Spark (2019). EDHREC ranks it #11,188 among Commander cards. It appears most in Ezuri, Stalker of Spheres decks (668 on EDHREC). 1 public deck on TCG runs it. It has 7 official rulings.

Legality

commander: legal
legacy: legal
vintage: legal
pauper: not legal
modern: legal
pioneer: legal
standard: not legal
brawl: legal

Public decks that run Roalesk, Apex Hybrid

Bedecked Brokers - New Capenna Commander, led by Perrie, the Pulverizer

Commanders that run Roalesk, Apex Hybrid most

Deck counts from EDHREC.

Often played with Roalesk, Apex Hybrid

Cards that show up in the same decks on EDHREC.

Rulings

2019-05-03: You proliferate twice all while Roalesk's last ability is resolving. Nothing can happen between the two proliferations, and no player may choose to take actions.
2023-02-04: Players can respond to a spell or ability whose effect includes proliferating. Once that spell or ability starts to resolve, however, and its controller chooses which permanents and players will get new counters, it's too late for anyone to respond.
2023-02-04: To proliferate, you can choose any permanent that has a counter, including ones controlled by opponents. You can choose any player who has a counter, including opponents. You can't choose cards in any zone other than the battlefield, even if they have counters on them.
2023-02-04: If a player or permanent has more than one kind of counter on it, and you choose for it to get additional counters, it must get one of each kind of counter it already has. You can't have it get just one kind of counter it already has and not the others.
2023-02-04: An ability that triggers "Whenever you proliferate" triggers even if you chose no permanents or players while doing so.
2023-02-04: You don't have to choose every permanent or player that has a counter, only the ones you want to add another counter to. Since "any number" includes zero, you don't have to choose any permanents at all, and you don't have to choose any players at all.
2023-02-04: If a permanent ever has both +1/+1 counters and -1/-1 counters on it at the same time, they're removed in pairs as a state-based action so that the permanent has only one of those kinds of counters on it.