Firewalker

Firewalker was a monstrous extra-dimensional entity and an enemy of both the Exiles and the X-Men, though the full extent of its powers were unknown - it was sufficiently powerful however to devour many of the Exiles (as explained below).

History
Amber Hunt encountered Firewalker from her previous passage in the red vortex between two dimensions when she first met her fellow Exiles.

The X-Men (Beast, Gambit, Rogue, Iceman and Storm) were looking for Juggernaut. Gateway, sitting atop the X-Men's jet, picked up a trail and used his whirling bola to open a dimensional rift that led to Earth-93060 (Ultraverse). Passing through a red swirling barrier, they encountered the Exiles, which included Siena Blaze, Reaper and Juggernaut (each an opponent at some point of the X-Men) from Earth-616. A fight quickly broke out; meanwhile, Gateway kept the portal open. Reaper sought to escape back to his home dimension and ran to the breach but was instead pulled into the giant toothed maw of Firewalker, which began to materialize in the rift. The others went to his aid, but several more went into Firewalker's mouth and it grew with each one, drawing energy only from the Exiles, stretching the breach wider. The victims were rescued and Firewalker shrank slightly as a result, thereby finding it easier to wriggle through, but Gateway shut the portal down, locking the beast away as it screamed for its "mother." Siena Blaze, Reaper and Juggernaut realized that Firewalker blocked their path home.

Despite this itt was not encountered again; the Earth-616 mutant Exiles returned to their home dimension via the transdimensional portal of Maxis, thereby bypassing the red vortex/barrier.