A vigil is when a cat must stay awake for the night in regards to some kind of tradition.

Warrior vigil:

Once a cat has received their warrior name, they are required to sit through a silent vigil that night to guard the camp. If the clan is in a situation where it is not possible for new warriors to carry out their vigil, they will usually be assigned another task in its place.

Deceased Clan Member:

If a clan cat dies, their body will be taken to the center of the camp. Close friends and family of the deceased cat will sit vigil for them through the night, and share tongues with them for the last time before the elders bury them in the morning. Vigils can also be held for cats without recovered bodies, or cats who are suspected to be dead.