Arthroverta
The Castlevania series does have a history of respecting its own continuity. Over the years, as the series brought in new monsters and new enemies, it built of a cadre of creatures (and locations for those creatures), crafting its own mythos around these beings. And yet, even with that eye towards continuity, there are still some lesser known creatures that the series has referenced where you wouldn't even know it.
You would be forgiven for not realizing there was even a connection between the Castlevania: Order of Ecclesia boss (the first one in that game) and enemies from the classic Game Boy titles (certainly we at The Inverted Dungeon didn't know it until the factoid was pointed out to us). First called "she-worms", these little creatures were more environmental nuisances than truly dangerous enemies.
And yet, you can see the resemblance between these tiny creatures (which roll around when disturbed) and the larger monster encountered in the last Nintendo DS title for the series. Yes, it's a bigger version than we saw in the past (although the series has a history pulling that trick, as evidenced by the Giant Merman), but it is, in essence, another she-worm. That's the kind of awesome reference that a series can pull off with such a long and rich history as Castlevania.
Fighting Against Arthroverta
In its first appearance in The Castlevania Adventure, the "she-worm" is a small enemy that appears in stage three of the game, the Torture Chamber. It will move back and forth, and will roll around when attacked, forcing the player to jump out of the way to avoid damage. A new version, looking more beetle-like than a worm, appears in sequel Castlevania II: Belmont's Revenge. Here, in the Rock Castle, the insectoid shows up in an area lit by candles. When the light is upon them, the beetles are immovable; however, if the candles are put out, the beetles wake up and become harder to dodge.
It's in Castlevania: Order of Ecclesia that we see their evolved form, though. After collecting Magnes, the first of heroine Shanoa's movement glyphs, the player will them come upon Arthroverta's boss chamber in the Monastery. Two Magnes orbs are near the top of the chamber, and this boss fight is, essentially, a training exercise for use of the glyph.
The giant she-worm has a simple and predictable pattern, so the player just needs to learn their attacks to win the day. Arthroverta can curl up into a ball and roll back and forth along the floor, forcing the player to float upwards via the Magnes glyph. If will them open up (revealing its beetle-like construction), showing its very human face. This face will spit out a web (or, in Hard Mode, webs) that will arc across the room. And, finally, it can use it pincer-like claws to melee at the heroine. Overall this is an easy fight, as befits the first boss of the game, and shouldn't prove that difficult for the player to defeat.
Arthroverta in Pop-Culture
Unlike many bosses and enemies in the series, Arthroverta has no basis in pop-culture, let alone mythology or religious texts. That said, as a Konami character the enemy has seen reference in another Konami title. Specifically, her appearance is likely based on Kimkoh, the alien demon from Contra III: The Alien Wars.