Slithering Cryptid

When this creature enters, create a Mutagen token. (It's an artifact with "{1}, {T}, Sacrifice this token: Put a +1/+1 counter on target creature. Activate only as a sorcery.")

"The Slithery! He's snatches little kids an' keeps 'em in cages! He don't got no legs and just slithers." —Lita