Minimum of three. Vogons, maybe? Just to add more layers of raw hate and bad poetry.
The Beast (Homeworld: Cataclysm), the Flood (Halo) and the Tyranids (Warhammer 40K). Drop the resultant unholiness onto Faerun, circa the Time of Troubles.
Yamato (Kantai Collection), Yamato (Arpeggio of Blue...