The Antiproton River is a river of antiproton matter in Lex Luthor's pocket dimension.
History[]
Infiltration into the Pocket Universe[]
The antiproton river formed in a Pocket Universe created by Lex Luthor, which he used to keep prisoners. While escaping the prison in the pocket universe, Superman fell into the antiproton while holding Joey Mason. Superman attempted to keep Mason out of the river while he was getting pulled under the surface. The river came up to a black hole, which Superman managed to escape before getting pulled past the point of no return with help from Krypto, Rex Mason, and Mister Terrific. Superman and Joey Mason were brought out of the antiproton river and left the pocket universe.[1]
References[]
The DC Universe Wiki has a collection of images and media related to Antiproton River.