I saw a sprite in Pokémon Go, but it didn’t look like a Pokémon I knew. It looked like a little dress with stubby arms, and a hollow oval on top. There was a dot in the center of the oval, just floating.
You probably saw this:
It’s a new Mythical Pokémon called Meltan. You can’t catch it yet, though, because it will turn into a Ditto.
This is what it looks like when you enter the battle:
More about Meltan