The ancient crystal can take 3 legendary actions, choosing from the options below. Only one legendary action option can be used at a time and only at the end of another creature's turn. The ancient crystal regains spent legendary actions at the start of its turn. Cast a Spell. The ancient crystal casts one spell that it can cast at will. Move. The ancient crystal moves up to half its speed. Slash (Costs 2 Actions). The ancient crystal makes one attack with its slash.