Pinkymod/Byg Rokker

The Byg Rokker is a Hardmode found in the Underground Hallow. It either slides along the ground if the player is currently standing or makes a large jump if the player is in the air.

Bestiary Entry
Demonic being from the Hallow. It may look like neatly carved rock cursed or bestowed life, but it is nothing like it seems. It is purely magical, a creation of the twisted lands that is the Hallow. A story goes around their creation, that there was a great and powerful mage that were amongst the first few explorers that stepped foot on the Hallow where it first came. Foolishly, she attempted to enter communion with the blue land, and it immediately seized control of her mind and threw her into a state of mania. She was then used by the land as a portal of all kinds of monstrosities, one of which was the Byg Rokker, spawned from the geometrical imaginations that passed her mind in her state of delirium.

Because of the fact that they are conjured entirely of thin air, they are more resistant to physical means of damage. Magical assaults are most effective when dealing with these abhorrent entities. Also unnaturally resistant to dark damage, unlike what one might expect of the Hallow's critters.

Knowing that the Lihzahrds and Hornets probably made these up, I am quite surprised to see that they didn't stick a thousand flamethrowers in it blasting 'Profaned Flame' or whatever dumb magic fire it is those lizardmen worship.