Shadonia

Shadonia is the het ship between Shadow and Sonia from the Sonic the Hedgehog fandom.

Canon
Sonia appears exclusively in Sonic Underground and briefly in the Underground Zone in the Pre-Super Genesis Wave Archie comics. Shadow was introduced a out two years after the last episode of the TV series.

However, Sonia has made an unintentional cameo in Sonic & Sega All-Stars Racing, a game in which Shadow is playable. The creators stated that they mistook a fan art of Sonia for official art of Amy Rose.

Fanon
The ship has a small following, though it is not the most popular ship for Shadow. It is among the most popular ships for Sonia.

Fandom
DEVIANTART