Source Book of the Damned Volume I: Princes of Darkness
Aura strong conjuration; CL 8th
This sickly yellow devils talisman summons a hellmouth that connects to the Hellish layers of Dis and Malebolge. Once per day you can open a 10-foot portal to either of these layers. This portal remains open for 10 minutes (or until you dismiss it) and functions as the spell gate.
The hellmouth summoned by this talisman is an amphisbaenic being known as Alksomasic, each of its two portal-heads appearing as a massive snake with three gigantic fly-like eyes. His maws connect to a shadowy alley in the city of Dis known as the Walk of Wayward Skins and to an outlying bolgia of Malebolge where monstrous worms slither through a waist-deep sea of ash.