Ultra Instinct, canonically called Ultra Instinct Sign (Check main wiki on DB for canon information Ultra Instinct Sign), or "UI" for short, is a form available to all races that can be bought at level 490 for 300,000 Zeni, found in the 'Other' section of the Skills Shop. The process of activating Ultra Instinct, once purchased, is vastly different when compared to activating most other forms.
Unlocked at level 490, prestige 0, for 300,000 Zeni.
Can only be attained by transforming once the player's Health and Ki are equal to or below 15%. Activating it will restore 100% of the user's Health and Ki.
Enormous Ki drain, exceeding Super Saiyan 3, Imperfect Golden, and Super Saiyan 4. This results in the form lasting for roughly 80 seconds.
Can't be used in Ranked Matches.
Cannot be manually deactivated. Ki must completely drain.
Attacks that would normally use up Ki will not, and will instead automatically refill the used-up Ki.
Fast flying and running is replaced with the player vanishing as if they using Instant Transmission.
Normal punches and heavy hits teleports the player to a close target.
There is no way to regenerate Ki (includes Senzu Beans/Jars and Ki charging).
50% Chance of auto-dodging almost any attack (Excluding rushes, guard breaks/heavy hits and quick melee moves). However, if the user gets hit once, the user will be able to get stuck in a combo (Similar to the Dragon Ball Xenoverse 2 Mui Goku Auto-dodge), however some moves still won't land (Kick Barrage, Super Spirit Bomb Sword, ETC...). Damaging your enemy will also cancel out most of his attacks, causing you to take no damage for long periods of times.
As of the Mastered Ultra Instinct update, you lose almost all health when losing the transformation, however there is no effect, unlike Mastered Ultra Instinct.
Omen has no hidden Ki max increase, unlike most other forms.
It has a two minute cooldown before being able to be used again.
This can be changed by charge-resetting. Doing so will make the cooldown timer 0.
A common tactic to transform into this is using Super Nova, Eraser Cannon or any Beam move and then aiming it at oneself.
Kaioken x4 Kamehameha and Tribeam spamming are also viable methods.