Level 1 — Green Dragon: Attacks apply a Corrosive poison that deals 25 magical damage per second for 3s. Affects buildings.
Level 2 — Red Dragon: Attacks gain splash damage dealing 75% of attack damage to all enemies within 275 AoE. Splash also applies Corrosive poison; other attack modifiers only affect the primary target.
Level 3 — Blue Dragon: Attacks also apply a Frost debuff (pierces Debuff Immunity) — 50 attack slow and 30% move slow. Splash attacks now apply both Corrosive poison and Frost to all affected units; other attack modifiers only affect the primary target.
Now also increases cast range of all abilities by 350 (doesn't affect items).
Upgrades to Level 4 Black Dragon: 40 Bonus Move Speed, 35 Corrosive Damage, 100% Splash Damage, 350 Splash Radius, 65 Attack Slow, 45% Movement Slow, +20% Magic Resistance, and free pathing.