Mutations

Mutations, introduced in the Foundry Update, are passive modifiers which replace Stat-based secondary effects from the Brutal Update. They can be obtained between levels from the NPC that formerly manned small shops holding only two Gear items.

Most mutations are not available initially - to unlock them for future selection, one must first bring their blueprints to the Collector, then spend the requisite amounts of cells.

Mechanics
The player can only benefit from a certain number of mutations at once. Each area cleared in a run allows the player to use one more mutation up to a hard limit of 3 mutations. However, the player can choose to spend gold between levels (cost starts at 2500 and scales with loot level) to remove all current mutations, allowing for a new set of mutations to be chosen to replace the old set.

Most mutations are associated with a specific stat (Brutality, Tactics or Survival), scaling their benefits based on their current levels. Specifically, base damage and healing magnitudes for these mutations are multiplied by (1.15^(n-1)), where n is the current level of the appropriate stat, and rounded to produce the final effect magnitudes (e.g. if a Brutality-scaling mutation provides 30 base extra DPS and the player's Brutality level is at 2, the final extra DPS is (90 * (1.15^(2-1))) = (90 * 1.15) = 103.5 ~= 104). Note that damage and DPS bonuses on attacks from mutations are not affected by gear-specific damage bonuses or Affixes.

General mutations, however, have fixed benefits which are not affected by the player's stat levels, and the cooldown-reduction mutation has its own unique scaling with Tactics.

Brutality Mutations
Artificer's scaling with Brutality is given in the following table:

Tactics Mutations
Efficiency's scaling with Tactics is given in the following table: