Invulnerable

Invulnerable is a buff effect that makes the target Untargetable by enemy abilities and immune to damage and debuffs, except Time Stop, for its duration. Invulnerable also removes all existing debuffs including Armor debuffs and hero-specific debuffs like Jaina's "Chill", with the exception of aforementioned Time Stop. Abilities with delayed effect, like Kael'thas' Living Bomb, are also nullified, when Invulnerable is applied. Unlike Stasis, Invulnerable heroes can be targeted by friendly abilities.

The Core
The Core is Invulnerable and cannot be attacked until both Fort and Keep in one lane has been destroyed.

Abilities

 * Standing in the Hall of Storms grants invulnerability.
 * Anduin's level 20 talent, "Light of Stormwind", adds an additional effect to his "Holy Word: Salvation" heroic, making allied Heroes within the area Invulnerable for up to 3 seconds, but not himself.
 * The Lost Vikings' level 13 ability, "Jump!", makes them Invulnerable for 1.5 seconds.
 * Medivh's trait "Raven Form" grants Invulnerability as long as he remains mounted.
 * Murky's ability, "Safety Bubble", makes him Invulnerable for 2 seconds.
 * Tyrael's level 10 heroic ability, "Sanctification", creates a field that lasts for 3 seconds. Allied heroes standing inside the field are Invulnerable.
 * His level 20 talent, "Holy Arena", increases the duration of "Sanctification" to 4 seconds.
 * Uther's level 10 heroic ability, "Divine Shield", makes an allied hero Invulnerable for 3 seconds.
 * His level 20 talent, "Bulwark of Light", increases the duration of "Divine Shield" to 4 seconds and also applies it to all nearby allies.
 * Yrel' level 20 talent, "Bubble Hearth", makes her Invulnerable for 6 seconds but forces her to use Hearthstone.