What happened to mettaton

Mettaton, in the time following the fall of New Home and the growth of the Hunger, did his best to maintain order and keep the monsters of the Underground informed of the happenings in their world, often placing himself at risk to help and foster those in need. Eventually, though, the riots in the capital became too much for him to stand against alone, and the resort erupted into chaos, a portal for those rushing to the capital to join the fighting and the feeding.

In the confusion, a stressed and vengeful cat monster saw his chance for revenge, and pushed Mettaton into the ravening crowd. In his newer, more destructible form, he was torn to shreds, only avoiding being destroyed entirely by retreating into the carapace of his older form and fusing his soul with the wiring.

It was a last resort to prevent his death, but resulted in an almost complete memory loss, his mind now run almost entirely by the Hunger and his robotic form. He reassembled himself as much as possible, and dragged himself into the CORE, in an attempt to follow the crowds into New Home. He became lost, however, never able to find the exit (or the entrance back into his now abandoned resort), and dwells in the swiftly deteriorating machine to this day, chasing and consuming any monster so unlucky as to find themselves in the tunnels of the CORE.