Level 1

Enhanced Contaminant - Increase Contaminate area by 35%

Acidic Compound - Contaminate deals 100% extra damage to minions and mercenaries over 3 seconds

Creep Skating - Generate Creep also increases ally move speed by 30%, lasting for 1 second after leaving creep

Level 4

Rapid Change - Changeling morphs instantly

Covert Changeling - Once Changeling has completed it's morph, it gains stealth for 10 seconds

Airborne Contamination - Heroes hit by Contaminate are blinded for 3 seconds

Level 7

Creep Expansion - Generated Creep spreads further, lasts for 2 seconds longer after Overlord moves

Low Density Creep - Generate Creep costs 4 less mana/second

Leeching Mass - Using Expel Biomass on an enemy will heal you for all damage done by it after 10 seconds

Level 10

Morph to Overseer - Morph into Overseer form, gaining increased vision and move speed, as well as the ablity to see stealth and move while generating creep

Mutate Ventral Sacs - Mutate Ventral Sacs allowing allies to enter Overlord for Stasis and large health regen

Level 13

Self-Destruct Gene - Changeling explodes upon death, dealing (422+4%) damage in an area around itself

Hardened Carapace - While Generate Creep is active, you take 30% less damage from all sources

Helium Synthesis - Rise higher up in the air for 5 seconds, becoming invulnerable to melee attacks and ground abilities, but taking 30% extra damage from ranged abilities

Level 16

Vampiric Goo - While Expel Biomass shield is active on an Ally, they also heal 75% of damage every dealt through auto-attacks

Critical Bio-Mass - Enemies affected by Expel Biomass become Vulnerable for the first 2.5 seconds, taking 25% extra damage from all sources

Tripled Potency - Contaminate gains three charges, increase cooldown per charge by 3 seconds

Level 20

Eye see you - Overseer lasts until death, but the cooldown only starts upon respawning

Superior Mutation - Ventral Sacs now gain the full health and mana regen amount of the Hall of Storms and can carry an extra hero

Pneumatized Carapace - Increase Overlord and Overseer base move speed by 20% and activate to increase by 60% decaying over 3 seconds (40 second Cooldown)

Biomass Overload - Overlord drops to 10% health and Expels Biomass onto all targets within range