Legendary Actions
Monsters › Parts of a Stat Block · SRD 5.2.1 p. 257
If the monster has Legendary Action options, those are listed in this section. A Legendary Action is an action that a monster can take immediately after another creature’s turn. Only one of these actions can be taken at a time and only after another creature’s turn ends. The monster can’t take a Legendary Action if it has the Incapacitated condition or is otherwise unable to take actions.
The monster has a limited number of Legendary Action uses, and that number is specified in the stat block. The monster expends one use whenever it takes a Legendary Action, and it regains all expended uses at the start of each of its turns.