Seems like they're preparing a new part of Time Temple.

if we consider the black mage as the goddess' personal nightmare, someone with a fraction of his power creating a sub-nightmare seems plausible, don't forget that, even if a person created a fake dream world withing maple, the black mage tore apart maple itself in big bang

...Eh, the Big Bang never made sense anyway.
"I'm gonna give you more convenient travel, better levelling and make you hella stronger! For the evulz"