"Whenever you encounter these creeping Worms make sure to finish them off. Use Fire Balls and watch your step!"
— Official Player's Guide
Arthroverta (アースロヴェルタ,Āsuroveruta?) is an enemy in the Castlevania series. It is a multi-segmented and multi-legged insect which tends to curl-up into a ball and roll around. They are sometimes referred to as "Worms", "Beetles", or "Snails".
In both games, the She Worms will just pace back and forth, but when struck they curl-up into a ball and roll around.
In concept art in the Castlevania Anniversary Collection, it is described as a "Giant Pill Bug" that rolls around quickly when attacked and will bounce off walls.
The Beetles stay immobile, curled-up in a ball when there's light. They are invulnerable but won't do any harm while in this state. However, when light goes out after nearby candles are destroyed, they will start to move around.
Arthroverta appears at the Monastery as the game's first boss. It is a giant beetle-like monster with a humanoid face hiding inside the carapace located on the upper part of its head. Its attacks are predictable and has relatively low health compared to later bosses.
It has three attacks:
Curls into a ball and rolls forward at high speed, violently ricocheting a couple of times on both the left and right walls of the room. Jump and cast Magnes to get attracted to any of the metal spheres above and remain airborne, out of Arthroverta's way.
Opens the carapace on top of its head, revealing a humanoid face that spits a web which arcs down on the player (on Hard Mode, Arthroverta fires several webs at once in a continuous stream).
Raises its giant claw and smashes it on the ground, trying to hit the player.
The last two attacks are used alternately. The Arthro Medal (gained for defeating Arthroverta without receiving any damage), hails it as the "Earth Beetle". There is no reward for defeating Arthroverta other than its medal, but inside the next room a cutscene will take place, and then Wygol Village –the main hub of the game– will become accessible on the world map.