From Pluralpedia, the collaborative plurality dictionary
blackeye (n.)

A blackeye is when headmates are in front but are physically unable to do anything with their own body or the collective body due to the actions of another headmate making them unable to. This usually comes with amnesia of what happens while the alter experienced blackeye. In some systems, this can cause physical or emotional harm to the alter experiencing blackeye.

Blackeye is usually used for magical/fairytale headmates although this can affect all headmates. Blackeye was originally called blackout before the coiner realized that blackout is usually used as an amnesia term.