Vanish Behaviour

What happens to a player when they vanish, and what they can still do.

When a player vanishes

They are hidden from every player who isn't allowed to see them (see Vanish Priority): gone from the world, the tab list and player-name tab completion.
The potion effects in when-vanished.give-potion-effects are applied with infinite duration. Effects they already had of the same type are remembered and given back on unvanish.
With when-vanished.fly.enable they can fly.
They get the vanished metadata that EssentialsX, DiscordSRV, TAB and many other plugins check.
If join-leave-messages.fake-leave-message-on-vanish.enable is on, everyone sees a fake leave message.

When a player unvanishes

They become visible again, their previous potion effects come back, and the /vanish interact override is switched off.
Flight is taken away only if vanishing granted it. Players who could already fly (creative, spectator, /fly) keep it. Others keep it too with when-vanished.fly.keep-on-unvanish: true or the advancedvanish.keep-fly permission.
If join-leave-messages.fake-join-message-on-unvanish.enable is on, everyone sees a fake join message.

Joining and leaving

A player with advancedvanish.vanish joins vanished when:

cross-server sync is on and the network says they were vanished, or else
keep-vanish-state is on and they were vanished when they last left (see Saved Vanish States), or else
vanish-on-join is on (the default), or they have advancedvanish.join-vanished.

Vanished players' join and quit messages are hidden unless when-vanished.join-messages or when-vanished.leave-messages is on. They are vanished before other plugins' join handlers run, so those plugins already see them as vanished.

When a vanished player quits, their effects and flight are restored quietly (no fake join message), so nothing lingers in their player data. The same happens to everyone still vanished when the server stops.

What vanished players can do

Each when-vanished option is false by default, which blocks the action.

Option	When `false`	`/vanish interact` lifts it
`send-messages`	Chat is blocked (`cannot-chat-while-vanished`)	no
`break-blocks`	Breaking blocks is blocked	yes
`place-blocks`	Placing blocks is blocked	yes
`interact`	Using blocks and items is blocked: doors, buttons, pressure plates, eating, throwing	yes
`open-and-use-chests`	Containers open silently and read-only	n/a
`pick-up-items`	Picking up items is blocked	yes
`drop-items`	Dropping items is blocked	yes
`attack-entities`	Attacking mobs is blocked	yes
`receive-damage-from-entities`	Mobs and players can't hurt them	no
`lose-hunger`	The hunger bar doesn't change	no
`mob-targeting`	Mobs ignore them	no

Two rules are fixed:

A vanished player can never attack another player. It would give them away.
A vanished player takes no damage from anything else (fall, fire, drowning, void). Only entity damage is controlled by receive-damage-from-entities.

/vanish interact

/vanish interact toggles an override for the current vanish session. While it's on, the rules marked "yes" above don't apply, so a staff member can open a door or break a block without unvanishing. It turns itself off when they unvanish.