User blog comment:Dispelling Mage/Omake: Lucy & Migi - Review/@comment-5303512-20150828193319/@comment-96.255.231.61-20150829035844

@CNBA3

Fairy Tail is a popular series owned by the same publisher as Parasyte, and Parasyte is in the middle of doing a bunch of one shot crossovers with other series, that's how.

It also helps that Fairy Tail is a fantasy series that relies on comedy. Something like Migi showing up isn't as out of place as it would be in say a sports series. Plus shared voice actor between Migi and Lucy.