OptionalsoundCreate a new variable. If the ID is already used, silently does nothing. isCloud is ignored if the sprite is not the stage or if the cloud variable limit has been reached.
OptionalisCloud: booleanLook for a variable by its ID in this target. If it doesn't exist in this target, will check if it exists in the stage target. If it still doesn't exist, returns undefined.
OptionalskipStage: booleanOptionalskipStage: booleanOptionalskipStage: booleanCalled by runtime when the green flag is pressed.
Mirrors custom state.