File this under weird crossover because Fairy Tail author Hiro Mashima and Kodansha which publishes Parasyte have teamed up for a one-shot crossover manga that features Fairy Tail's Lucy and Parastyes Migi meeting. The manga was published in the October issue of Afternoon which came out in Japan on August 25th. Fairy Tail is a fairly light hearted action manga and Parasyte is a pretty intense horror manga. So why are they teaming up? Well, it's all part of the Neo Parasyte homages to Parasyte. You can expect the homage to be fairly light hearted as well which keeps in line with the tone of Fairy Tail.
[source Comic Plus Twitter]