The Rare Pepe collection spawned a significant amount of experimentation on Counterparty, one of which was UFOPEPE.
This card is considered the first GIF to be linked to a Counterparty asset. It was minted by a user named 'Mike' who was the creator and curator (sometimes called 'scientist') of the collection.
While there was a token created before that mentioned 'gif' named MEMETOKEN, UFOPEPE is the first true use of a piece of artwork in GIF format that was minted with the token originally.