Universal remnant blackhole 

A blackhole that was created by a dying (exploding, collapsing, etc.) universe.

'The previous universe grew so cold that all the stars faded into blackholes, merged and eventually grew into a universal remnant blackhole, which was so massive that it swallowed the entire universe, but fear not for a new universe could be reborn from it.'

Universal remnant blackhole by DianaLuciusDeCollis July 30, 2022