Here’s the complete story:
The Yolkian’s search was over. After many years, decades, and even centuries of trying to find the most perfect lifeforms out there, they have finally found a “goldmine.” And so, on that very faithful night, the many inhabitants of Equestria were greeted by a large fleet of chicken-shaped spacecrafts, and afterwards, not only did the spacecrafts leave, but so did half of Equestria’s population. It turns out the Yolkians were preparing their annual ceremony hosted on their home planet of Yolkus, a ceremony in which they worshipped to their almighty goddess, Poultra; and so King Goobot and his empire decided that the many of the Ponies, Unicorns, Alicorns, Dragons, Buffalo, and much more of Equestria were worthy to become participants in their grand event, and with the help of the Yolkian’s advanced and otherworldly technology, it seemed like they wouldn’t have minded doing the Yolkian’s questionable dance ritual in front of their goddess.