What's with the unicorns??

Several months ago I noticed that suddenly there are a bunch of fruity unicorns under the "Frequently Used" section of my emoji's. Never once have a used a unicorn, so I don't know why they're there.

I thought that with time they'd go away as I continue to use other icons, but no, they're still all front and center.

This is only on my iPhone, no other devices...

Any idea why this happened? Or how to remove them from the Frequently Used section?