'Bottomless' in the Bible
He answered, "Legion," because many demons had gone into him. Then the demons began begging Jesus not to order them to go into the bottomless pit.
When the fifth angel blew his trumpet, I saw a star that had fallen to earth from the sky. The star was given the key to the shaft of the bottomless pit.
It opened the shaft of the bottomless pit, and smoke came out of the shaft like the smoke from a large furnace. The sun and the air were darkened with the smoke from the shaft.
They had the angel of the bottomless pit ruling over them as king. In Hebrew he is called Abaddon, and in Greek he is called Apollyon.
When they have finished their testimony, the beast that comes up from the bottomless pit will wage war against them, conquer them, and kill them.
The beast that you saw existed once, but is no longer, and is going to crawl out of the bottomless pit and then proceed to its destruction. Those living on earth, whose names were not written in the Book of Life from the foundation of the world, will be surprised when they see the beast because it was, is no longer, and will come again.
Then I saw an angel coming down from heaven, holding the key to the bottomless pit, with a large chain in his hand.
He threw him into the bottomless pit, locked it, and sealed it over him to keep him from deceiving the nations anymore until the thousand years were over. After that, he must be set free for a little while.