Echobeast

Echobeast is the sleep-loving Guardian that serves as the boss of Echocave. Upon defeat, he drops Crystal Wave for Nina, or Echo Shell for Ace.

Attacks
At the beginning of the fight, Echobeast will always teleport to a random surface on the arena (indicated by a red ! mark), and create two indestructible sound waves that bounce around the arena. After this, he will teleport again and begin the proper fight. His attacks are always determined by which surface he's on. If he is on the floor or the ceiling, he will stomp the ground, creating crystals on top of the arena that fall one by one in a random order. If he is on a wall, he will throw four crystals towards the player, with a larger gap between the middle two crystals for the player to stand between. After attacking, he will either teleport to a new location, or curl up into a ball and roll to the opposite surface, then teleport.

Once significantly damaged, Echobeast goes into an enraged "whack-a-mole" phase, indicated by a color change, where he will constantly spam the same attacks until he is damaged, then teleport and repeat the process. After a while, this enraged phase will end and Echobeast will launch a second set of sound waves before going back into his initial phase.

Tips
Ace's Osafune and Nina's Negation Pulse (both dropped from Legacy) are the only things capable of destroying Echobeast's sound waves.

If Echocave appears as Stage 1, Echobeast will not spawn the second set of sound waves following his enraged phase.