The Pool of Forevers was a device created by the Time Gods of Chronux to travel through time. After killing all but one of the Time Gods, Gorr used it to travel back in time to before the beginning of the universe, killing a baby Elder God to steal its heart. Following a skirmish with Thor Odinson, Gorr used the Pool to travel untold millennia into the future, arriving in Earth-14412.
Over the next 900 years, Gorr used enslaved gods to build the Godbomb around a Pool of Forevers, intending to send the living abyss of the All-Black symbiote back through time to kill every god that had ever existed. Gorr used this Pool of Forevers to pull gods out of the timestream, and send Black Berserkers into the past to capture Thor's younger self and bring him to the future, intending him to be the final sacrifice. Gorr's Pool of Forevers was destroyed with the detonation of the Godbomb, but Gorr's plan was foiled by the two Thors of Earth-616 and the Thor of Earth-14412.