Mewthree

This is mewthree its dex number is 290

more info-

This pokemon is type blend which at least makes sense because its a mix of mew and mewtwo

Its height is 6'11'' and its weight is 310.0 pounds

Its Pokedex number is the same as nincada (gen 3)

This pokemon looks simuliar to the mega evolution of mewtwo which is more for Y

Its pokedex states "The second attempt at cloning a MEW. It uses powerful pyshic abilities and fighting techquies"

This states its possibly a fighting type too like its X evolution.

A very similar version is used as Mewtwo's Mega Evolution.