Nacreum
The Nacreum is a transdimensional prison composed of intelligent nacre (nonfiction).
Description
The Nacreum was built to hold slippery characters such as The Eel.
Spider-Man (nonfiction)
The Nacreum would be delighted to confine Spider-Man (nonfiction) for an issue or two.
This offer is contingent upon DC Comics (nonfiction) and myself (nonfiction) (as the Nacreum's agent) agreeing to terms beforehand.
Abalonia and Gnotilus
The Nacreum is (usually) located in Abalonia.
Gnotilus, the founder and first citizen of Abalonia, keeps many of his prisoners in the Nacreum.
Mobility
The Nacreum can travel quite widely in time (nonfiction) and space (nonfiction)
It does this independently of Albonia, which has similar abilities.
This time-space travelling ability is presumed (by whom?) to be some form of the Gnomon Algorithm.