Genesis Portal

A Genesis Portal is a gateway that exists within different realities and allows for traveling between them.

History
The Genesis Portals came into being as a result of Doctor Eggman interfering with Sonic the Hedgehog's attempt to restore their world through Chaos Control. (Sonic the Hedgehog #251)

They were first discovered 200 years later by a scientist named Professor Von Schlemmer, who explained to Silver the Hedgehog what they were and what caused them, as well asking him to further investigate the portals.

Silver went back in time and aided Sonic in chasing The Ifrit back through a Genesis Portal that it emerged from as well as explaining the nature of the portals to the latter. Unknown to the two, Eggman was spying on them and thinking of how to use the Genesis Portals to his benefit. (FCBD 2015)

Shortly afterwards, Sonic is in pursuit of Metal Sonic to retrieve a Chaos Emerald. They both go through a Genesis Portal leading them from the Cystal Desert Zone to the Burning Ruin Zone.

The former is aided by the arrival of Silver who has been closing further portals that have opened. Silver is able to help Sonic to claim the Emerald, as well as finding another portal to send him back home, though he and Metal Sonic end up through separate Genesis Portals. Both of which land them in different, unknown dimensions. (Sonic Universe #75)

In a jungle within an alternate continuum in Sonic's multiverse, Sticks the Badger comes upon a Genesis Portal with an unidentified individual emerging from it. (Sonic Boom #7)

In Mega Man's world, Sigma shows up during the year 20XX to abduct Dr. Wily through a portal. (Mega Man #49)