Mutators

• Mutators are modifiers to enemies that spawn in the Onslaught game mode. You will be able to see with what lanes get x modifier(s) before starting. These can be an advantage or disadvantage to the enemies or can grant additional effects.
• Double Mutators start at floor 22.
• As of the Shifting Sands Update Pain Aura has been removed due to poor performance. To compensate, Bloodlust, Trollblood, Speed Demons, Berserked, and Reckless has been added to the game.

Credits to community member Arti for finding the numbers

Name	Icon	Description	First Floor Found on	Notes
Headstrong		Enemies cannot be stunned.	Floor 3	Don't use stunning defenses on these lanes.
Pile it on		Enemies take increased damage per condition they are under.	Floor 3	+25% additive extra damage if conditions are met. Conditions are the same things for Controlled Burn.
Power Block		All enemies are immune to damage from Abilities, but take increased weapon damage.	Floor 3	Don't use abilities. Hero Attacks deal +100% damage.
Unstoppable		Enemies are immune to slow effects.	Floor 3	Don't use slowing defenses on these lanes.
Abominable		Enemies inflict slow with their attacks.	Floor 3	Enemy attacks reduce defense rate by ~30%.
Soft Spot		Enemies have increased resistance, but take extra weakpoint damage.	Floor 3	Deals extra damage to weakpoints, otherwise 20% less damage (defenses can't hit weakpoints).
Armored		Enemies take reduced Physical damage, and increased Magical damage.	Floor 3	Use magical defenses, +25% from magical damage, -50% if you use physical damage. When combined with Soft Spot its 60% less physical damage and normal magic damage.
Toxi-kaze		When Kobolds die, they will leave an area that deals damage to players inside.	Floor 6	Kobold's death drops mushrooms that deals 2% hero's maximum health per second and each stack.
Lethargic		Enemies start stronger, but get weaker the longer they live.	Floor 9	Enemies deal 125% extra damage, over 25 seconds they'll deal 75% of their original damage.
Brittle		Enemies start with higher health, but receive a damage resistance debuff every time they are hit with hero abilities.	Floor 9	Enemies gain 50% extra health. Use unique abilities to debuff them by 10%, has Additive stacking.
Wall Leech		Enemies heal when damaging towers.	Floor 10	Enemies heal for 10% of their maximum health on hit.
Maximum Effort		Enemies have more health, but get weaker with each unique source of damage that hits them.	Floor 10	Enemies gain +50% health and take 10% increased damage per unique source with additive stacking. Each source can be added through different defenses, elemental combos, attacks, pet and hero abilities.
Phased		Enemies move slower, but they can phase through blockades.	Floor 10	Enemies move at around ~65% of their original speed and no longer target blockades.
Proximity		The closer a source of damage is to an enemy the more damage it deals.	Floor 10	+50% damage at 0 range and -50% damage at 5,000+ range.
Long Shot		The farther a source of damage is to an enemy the more damage it deals.	Floor 10	+50% damage at 5,000+ range and -50% damage at 0 range.
Enraged		Enemies start weaker, but get stronger the longer they live.	Floor 10	Enemies start at 75% of their original attack damage and eventually rises to 125% over 25 seconds.
Cursi-Kaze		When Kobolds die, they will leave an area that debuff towers and defenses.	Floor 13	Kobold's deaths Reduces the range, damage and attack rate of the affected defenses by 25% per stack, stacks are multiplicative.
Controlled Burn		Enemies can only be damaged while drenched, oiled, frozen, poisoned, chilled or stunned.	Floor 20	Use defenses or abilities to apply one or more of the listed conditions.
Detonator		Enemies explode when killed.	Floor 20	Explosions has knockback and deals 5% of the target's maximum health.
Bullet Sponge		Enemies have a small anti projectile shield.	Floor 20	The shield will be removed after dealing 10% of enemy health as damage. The enemey will take damage as normal as soon as the shield is removed.
Pain Aura (Removed)		Enemies deal damage around them.	Floor 20	Enemies Deal 5% of the target's maximum health as damage around them. Once per second.
Spellbreaker		Enemies take reduced Magical damage, and increased Physical damage.	Floor 20	+25% damage from physical damage and -50% damage from magical damage. When combined with Soft Spot its 60% less magical damage or normal physical damage.
Vampiric		Enemies heal when dealing damage.	Floor 20	Enemies heal for 5% of their maximum health on hit.
Bloodlust		Enemies on receiving damage now move at +30% speed for 5 seconds.	?
Trollblood		Enemies now heal for +2% of their max hp every second.	?
Speed Demons		Enemies are faster, but slow effects last longer on them.	?	Enemies move 50% faster.
Berserked		Enemies now take +50% more Damage and deal +50% more Damage.	?
Reckless		Enemies now have +50% Movement Speed and +50% Damage taken.	?