Cheapest priced copy (Double Masters 2022): $0.35 at Card Kingdom, near mint, their price list as of .
Experiment One 
Creature — Human Ooze · 1/1 · Uncommon · The List · #C15-184
Evolve (Whenever a creature you control enters, if that creature has greater power or toughness than this creature, put a +1/+1 counter on this creature.)
Remove two +1/+1 counters from this creature: Regenerate it. (The next time this creature would be destroyed this turn, instead tap it, remove it from combat, and heal all damage on it.)
Legal inCommanderPioneerModernLegacyVintagePauper
Not legal inBrawlStandard
8 printings · $0.35 to $0.79 at Card Kingdom
| Set | Number | Rarity | Card Kingdom | Foil |
|---|---|---|---|---|
| Double Masters 2022 | 146 | Common | $0.35 | $0.49 |
| Commander 2015 | 184 | Uncommon | $0.35 | — |
| Friday Night Magic 2013 | 9 | Rare | — | $0.69 |
| RNA Guild Kit | 111 | Uncommon | $0.35 | — |
| Gatecrash | 119 | Uncommon | $0.39 | $0.49 |
| The List | C15-184 | Uncommon | $0.35 | — |
| Ravnica Remastered | 137 | Uncommon | $0.35 | $0.49 |
| Ravnica Remastered | 346 | Uncommon | $0.35 | $0.79Out of stock |
7 rulings from Wizards of the Coast
- 15 April 2013When comparing the stats of the two creatures for evolve, you always compare power to power and toughness to toughness.
- 15 April 2013When comparing the stats as the evolve ability resolves, it's possible that the stat that's greater changes from power to toughness or vice versa. If this happens, the ability will still resolve and you'll put a +1/+1 counter on the creature with evolve. For example, if you control a 2/2 creature with evolve and a 1/3 creature enters the battlefield under your control, it toughness is greater so evolve will trigger. In response, the 1/3 creature gets +2/-2. When the evolve trigger tries to resolve, its power is greater. You'll put a +1/+1 counter on the creature with evolve.
- 15 April 2013If evolve triggers, the stat comparison will happen again when the ability tries to resolve. If neither stat of the new creature is greater, the ability will do nothing. If the creature that entered the battlefield leaves the battlefield before evolve tries to resolve, use its last known power and toughness to compare the stats.
- 15 April 2013If a creature enters the battlefield with +1/+1 counters on it, consider those counters when determining if evolve will trigger. For example, a 1/1 creature that enters the battlefield with two +1/+1 counters on it will cause the evolve ability of a 2/2 creature to trigger.
- 15 April 2013Whenever a creature enters the battlefield under your control, check its power and toughness against the power and toughness of the creature with evolve. If neither stat of the new creature is greater, evolve won't trigger at all.
- 15 April 2013If multiple creatures enter the battlefield at the same time, evolve may trigger multiple times, although the stat comparison will take place each time one of those abilities tries to resolve. For example, if you control a 2/2 creature with evolve and two 3/3 creatures enter the battlefield, evolve will trigger twice. The first ability will resolve and put a +1/+1 counter on the creature with evolve. When the second ability tries to resolve, neither the power nor the toughness of the new creature is greater than that of the creature with evolve, so that ability does nothing.
- 12 January 2024Because damage remains marked on a creature until it's removed as the turn ends, nonlethal damage dealt to Experiment One may become lethal if you remove +1/+1 counters from it during that turn. In this case, it dies before the activated ability that would regenerate it resolves.