Invulnerability

Invulnerability is a buff that renders the target completely immune to all crowd control and damage, with the exception of direct HP removal. The only spell effects that apply to a unit under invulnerability are friendly-only movement spells like Chen's Test of Faith, even effects not stopped by magic immunity. Magic immunity applied to a friendly invulnerable unit will remove the buff, but the application of invulnerability will never remove magic immunity itself.

These rules also apply to banished units.

Many abilities that cause invulnerability also allow (phasing) no-clip, but this is not an inherent property of invulnerability itself.

Omniknight's Guardian Angel does not provide true invulnerability, but is in fact the bestowment of 1000 armor. Buildings made invulnerable are only immune to damage and not appropriate spell effects as well, including both Glyph of Fortification and Naga Siren Song of the Siren invulnerability.