I was browsing through some My Little Pony crossovers (for my own amusement), when I came across these abominations- And I'm pretty sure they're all trollfics.

Sanic and Tals http://www.fanfiction.net/s/7699609/1/bsanicbndtals

Rainbowdash goes to the Mushroom Kinkdom <a href="http://www.fanfiction.net/s/7449982/1/RainbowdashGoesToTheMushroomKinkdom">http://www.fanfiction.net/s/7449982/1/RainbowdashGoesToTheMushroomKinkdom

Sonci Rainbow Dash and Robokinis Machine
<a href="http://www.fanfiction.net/s/7680290/1/SonciRainbowDashandRobokinisMachine">http://www.fanfiction.net/s/7680290/1/SonciRainbowDashandRobokinis_Machine

...There's not much else I can say about them except they're all terrible.