Non-targetable

Untargetability is a mechanic that makes the unit untargetable.

Definition

Mechanic	Definition	Examples
Non-targetable	Does not includes Hide sources. Grants Attack Immunity and Phased. Not selectable, removes Selection Box. Cannot be targeted by both allies and enemies.	Hitch A Ride
Misc Non-targetable	Can be selectable and still has a Selection Box. However, it cannot be targeted by either allies or enemies.	Smoke Screen

Unselectability

Main Article: Selection Boxes

Unselectability makes the unit not selectable, and selectable only in a few cases. Most abilities/items treat unselectable units as if they were invisible, except in a few cases. Some sources of unselectability may remove a unit's selection box, grant attack immunity, and may prevent allies or enemies or both from targeting them.

Although Hide sources also cause the unit to be unselectable and non-targetable, they are considered a different mechanic.

Sources

Unselectability Sources

Crystal Maiden - Crystal Clone

The created illusion is unselectable by both factions.
Illusion Selection Box is removed.
The illusion is not attack immune and units can walk through her.
Enemy units can still attack the illusion with a ground-targeted attack on the nearest unit.
Dark Willow - Shadow Realm

Dark Willow is unselectable by by both factions.
Her Selection Box is not removed.
She is attack immune and phased.
Can choose itself as a target.
Riki - Smoke Screen

The affected enemies within the radius are unselectable by their allies.
Enemies Selection Box is not removed.
They are not phased and not attack immune, but they cannot be attacked by their allies.
Phantom Assassin - Blur

Phantom Assassin is unselectable by enemy faction.
Her Selection Box is not removed.
She is attack immune, but not phased.
Ringmaster - Escape Act

Affected hero is unselectable by both factions.
Removes Selection Box.
Affected hero is attack immune and phased.

Unselectable by both factions, Invulnerable, Selection Box Removed

Ember Spirit – Sleight of Fist
Juggernaut – Omnislash
Juggernaut – Swiftslash
Meepo – MegaMeepo Fling
Outworld Destroyer – Astral Imprisonment^2b

Unselectable by both factions, Invulnerable, Selection Box Removed, Phased

Centaur Warrunner – Hitch A Ride
Mars – Bulwark (Soldiers) ^2a
Outworld Destroyer – Astral Imprisonment ^2b

^2a Requires

Aghanim's Scepter.

^2b Requires

Aghanim's Shard.

When a unit is granted unselectability, any attack or ability targeting it by the group of units that it is untargetable against (e.g. allies for Smoke Screen, all units for other sources) which are already in its attack or cast animation get canceled. For example,

A unit is being targeted by an enemy channeling Fiend's Grip and an ally channeling Life Drain. Another ally casting Book of Shadows on this unit will cancel the channeling Fiend's Grip but not Life Drain.

Bypassing Unselectability

Directly Unit-Targeting

Main Article: Target Unit

Target unit abilities require the caster to directly target a unit, and cannot be used on the ground. While most unit targeting abilities cannot target unselectable units, there are a few particular exceptions. These exceptions do not work on abilities that prevent both factions from targeting a unit.

Spell Reflection sources, and some abilities with an instant cast time that does not require facing the target while casting, can fully target unselectability from Shadow Realm and Smoke Screen.

No-Facing Target Required with Instant Cast Time Abilities on Enemies

Pugna - Decrepify

Can be casted to an enemy unit affected by Shadow Realm if channeling with innate Oblivion Savant.

No-Facing Target Required with Instant Cast Time Abilities on Allies

Bounty Hunter - Friendly Shadow

Can be casted to an ally hero affected by Smoke Screen or Shadow Realm.
Lich - Frost Shield

Can be casted to an ally unit affected by Smoke Screen or Shadow Realm if channeling Sinister Gaze.
Pugna - Decrepify

Can be casted to an ally unit affected by Smoke Screen or Shadow Realm if channeling with innate Oblivion Savant.

Secondary Targets

Additionally, most abilities also treat unselectable units as if they were invisible. Generally, abilities that do or do not affect invisible units also do and do not affect unselectable units respectively. For example, Paralyzing Cask neither bounces to invisible units nor unselectable units; Thundergod's Wrath neither strikes invisible units nor unselectable units.

However, the following abilities interact differently with unselectable units:

Sources Affecting Unselectable Units

Abaddon - Mist Coil

Visually launch projectiles to both invisible and unselectable units, but the projectiles against invisible units are instantly disjointed. Fully affects unselectable units.
Dust of Appearance - Reveal

Fully affect invisible units. However, it does not damage or slow unselectable units.
Hoodwink - Bushwhack

Fully affect unselectable units from Shadow Realm and Blur while not affecting invisible units.
Hoodwink - Decoy

The lesser Bushwhack affect unselectable units from Shadow Realm and Blur while not affecting invisible units.
Queen of Pain - Shadow Strike

Visually launch projectiles to both invisible and unselectable units, but the projectiles against invisible units are instantly disjointed. Fully affects unselectable units.
Spirit Breaker - Charge of Darkness

When current charge target dies, can change target to a nearby unselectable unit from Shadow Realm and Blur but not invisible units.
Undying - Tombstone

Partially affects unselectable units.
The Tombstone does not spawn Undying Zombies to attack nearby unselectable units as well as invisible units. But the zombies spawned do not die when the attacked unit is granted unselectability.
Weaver - The Swarm

The Beetles fully latch on unselectable units and applies its first damage instance then dies after 0.13 seconds. If a unit is invisible, beetles ignore it.
Wraith King - Reincarnation

Visually launch projectiles to both invisible and unselectable units, but the projectiles against invisible units are instantly disjointed. Fully affects unselectable units.