Ew Gay is a series of images depicting ponies flinching away from something and saying "EW GAY."
The image's origins are mostly unknown, though it was submitted to Ponibooru the night of the finale. It began with the still shot of Lyra, a background pony, as seen in the image to the right. Lyra was possibly chosen for the image due to her fandom relationship with Bon-Bon, another female background pony. The Bon-Bon/Lyra relationship was so wildly accepted, that making Lyra homophobic was a joke. Soon, the image gained popularity. It was placed on images of gay/lesbian shipping, and used in "Shipping" threads. The image was also edited to feature different ponies and different text.
Notable versions include Rainbow Dash saying "Ew Heterosexual," a play on the character's widely percieved lesbianism and the symbolisation of homosexuality as a rainbow, and Derpy Hooves saying "Ew Raisins," likely referring to raisin muffins (also known as sultanas), which several pieces of fanwork have depicted Derpy disliking. Other versions have appered since.