alternate dimensions

What Mad Universe – A pulp fiction magazine editor is transported into another universe where an intergalactic war is going on, major cities are under complete blackouts, and he is being hunted for being an Arcturian spy.

The Heads of Cerberus – A vial of the Dust of Purgatory transports several people to the gateway dimension of Ulithia. From there they journey to the hell of Philadelphia in 2118.