Mutations in Merge a Nuke are modifiers that attach to individual nukes and change how they perform, adjusting cash earnings, damage, health, and launch cooldown. Each one mixes an upside with a trade-off, so the “best” mutation depends on how far you are in the rebirth system and whether you are farming cash or pushing raid damage.
Quick answer: Reach Rebirth 3 to start spawning mutated nukes. Use Dense Core or Enriched Core early, switch to Overclocked Reactor in the mid-to-late game, and target Apex Core once you hit Rebirth 10.
Rebirth requirements to unlock mutations
The mutation system is gated behind rebirths. You cannot see or roll any mutation until you complete Rebirth 3, and higher rarities stay locked until you rebirth further.
| Requirement | What it unlocks |
|---|---|
| Rebirth 3 | Mutations begin spawning on nukes |
| Rebirth 5 | Legendary mutations become available |
| Rebirth 10 | Admiral mutation unlocks, plus a second mutation slot |
At Rebirth 10, a nuke can hold two mutations at once. The Magma mutation is the one exception to this ladder, since it comes from a timed event rather than a rebirth level.
How to get and transfer mutations
Once you are past Rebirth 3, mutations appear through two paths. Both rely on chance, so you cannot force a specific roll directly.
Note: Legendary mutations have a 10% chance to roll as Stabilized. A Stabilized mutation keeps its buffs but applies no debuff, which makes it the ideal version of any Legendary roll.
All mutations and their effects by rarity
There are 16 mutations in total. Fifteen appear in the in-game Index and roll normally, while Magma is event-only. The tables below list every confirmed mutation with its exact buffs and debuffs.
Common mutations
| Mutation | Effects |
|---|---|
| Dense Core | +25% cash, +25% health, +40% launch cooldown |
| Enriched Core | +40% cash, -25% health |
| Accelerated Fuel | -35% launch cooldown, -25% damage |
| Reinforced Plating | +50% health, -25% cash |
Rare mutations
| Mutation | Effects |
|---|---|
| Critical Mass | +50% damage while below 50% health, -25% cash |
| Leeching Warhead | Restores 25% health after a successful hit, +25% launch cooldown |
| Regenerative Alloy | Slowly heals after avoiding damage, -20% cash |
Epic mutations
| Mutation | Effects |
|---|---|
| Siege Core | +75% damage, +50% launch cooldown |
Legendary mutations
| Mutation | Effects |
|---|---|
| Fission | Spawns an extra lower-tier nuke when merged, -30% cash, -20% health |
| Overclocked Reactor | 2x cash, +75% damage, -40% health, +35% launch cooldown |
Admiral mutation
| Mutation | Effects |
|---|---|
| Apex Core | +150% cash, 2x damage, no downsides |
Some Epic and Admiral entries still show as unnamed placeholders in the Index for players who have not rolled them yet. The mutations above are the ones with confirmed names and values.
Magma: the event-only mutation
Magma does not appear in the mutation Index and cannot be rolled through normal spawns or merges. It only comes from the Volcano Event, which the developer triggers during the Admin Abuse event, regardless of your rebirth level.
While the event is live, a large volcano sits at the center of the map. You damage it by hitting its weak points, and every 15 hits on those weak points the volcano throws lava at the player with the most successful hits. That lava has a chance to apply Magma to your nukes. If a Lava Merge event is active, you can also pick up Magma by merging nukes.
Magma gives +50% cash and extra damage, and it sets the impact area on fire. The fire is cosmetic and deals no additional damage.
Best mutations to use at each stage
Because every mutation carries a downside, the right pick changes as your account grows. These are the safest and strongest choices for each phase.
| Stage | Recommended mutation | Why |
|---|---|---|
| Beginner (Rebirth 3) | Dense Core | Balanced cash and health with only a cooldown penalty |
| Early cash farming | Enriched Core | Biggest early cash boost for a small health loss |
| Mid-to-late game | Overclocked Reactor | Doubles cash and adds heavy damage once you can absorb the drawbacks |
| Endgame (Rebirth 10) | Apex Core | Large cash and damage gains with no downside at all |
Apex Core is the clear endgame goal since it is the only mutation with pure upside. Until you reach Rebirth 10, an Overclocked Reactor rolled as Stabilized is the next best thing, because the Stabilized version strips its health and cooldown penalties while keeping the 2x cash and bonus damage.
How to confirm a mutation is active
A mutated nuke shows its mutation on the piece itself, and each confirmed mutation is logged in the in-game Index. If a merge did not carry the mutation over, the inheritance roll simply failed, which is expected since transfers are chance-based. Keep merging mutated nukes into higher tiers until the roll succeeds, and remember that Legendary and Admiral options will not appear at all until you meet the Rebirth 5 and Rebirth 10 requirements.
