Untargetability refers to units in a state where they are no longer valid targets for auras (e.g. 
Sunfire Cape), unit-targeted (e.g. 
Disintegrate), auto-targeted (e.g. 
Requiem), direction-targeted (e.g. 
Mystic Shot) and ground-targeted effects (e.g. 
Pillar of Flame), including attacks, abilities, items and summoner spells. Becoming untargetable is not a form of invulnerability, and units will still suffer the effects of active applied damage over times (e.g. 
Ignite), delayed detonations (e.g. 
Time Bomb) and tethers (e.g. 
Drain).
The act of becoming untargetable will also interrupt any effects that have already acquired the unit as a target (e.g. an oncoming basic attack will fizzle) as well as causing AI-controlled units (e.g. turrets and minions) to acquire a new target (also known as "dropping aggro").
The telegraph from 
Karthus' Requiem will be placed on untargetable enemies, although the damage itself is classified as auto-targeted effect that occurs at the end of the channel time.
Examples
- Champions
Camille's The Hextech Ultimatum- Elise's Rappel
- Fizz's Playful
- Kayn / Rhaast's Umbral Trespass
- Karthus' Death Defied (post-death effect)
- Kog'Maw's Icathian Surprise (post-death effect)
- Maokai's Twisted Advance
- Master Yi's Alpha Strike
- Tahm Kench's Devour
- Urgot's Fear Beyond Death (Enemy champions)
- Vladimir's Sanguine Pool
- Xayah's Featherstorm
- Structures
- All turrets are untargetable while a lower tier turret in that lane remains standing.
- Destroying any inhibitor makes the nexus turrets targetable while one remains destroyed.
- An inhibitor is untargetable while a turret remains standing in front.
- The nexus is only targetable while both its turrets as well as at least one inhibitor are destroyed.
- The Nexus Obelisk is always untargetable.
Azir's 
Sun Disc and 
Zz'Rot Portals do not affect the above untargetability parameters.
Similar Effects
- Template:Cctip
Stasis applies all the effects of becoming untargetable, but also makes the target invulerable and unable to act.
- Kled while Skaarl's health bar is reduced to Zero.
- Sion's Glory in Death while reviving.
- Aatrox's Revive while reviving.
- Bard's Tempered Fate
- Kalista's Fate's Call
- Lissandra's Frozen Tomb (self-cast)
- Sion's Roar of the Slayer (displaced unit can still be targeted by Sion's Smite, but won't be dealt any damage by it. This may be a bug)
- Syndra's Force of Will
- Zilean's Chronoshift while reviving.
- Guardian Angel while reviving.
- Wooglet's Witchcap
- Zhonya's Hourglass
- Template:Cctip
Vanish (also referred to as Removed From Play) applies all the effects of becoming untargetable, but also makes the target invulerable, unable to act and invisible.
PENDING FOR TEST: There's claims that 
Ekko's 
Chronobreak will break tethered abilities, even if he does not leave their range.
Template:Ability types