Function: BreatheUnderwater(spawn, enabled)
Description:
Sets the entity's underwater breathing flag. When the current spell has targets, applies the flag to those entity targets instead; otherwise uses spawn.
Parameters:
spawn(Spawn) - Entity used when there is no current spell target list.enabled(boolean) - Whether underwater breathing is enabled.
Returns: None.
Original spell targets: When this function uses a spell's target list, it snapshots references to the originally selected actor allocations. It skips unavailable or departed targets instead of selecting another actor with a reused runtime ID. Accepted actors remain physically retained through the active protected callback, including Lua errors; saved userdata and target records do not keep them alive between callbacks. Explicit Spawn arguments retain their existing selection behavior. See Lua actor lifetime.