Ursula, Menace of the Deep

Menace
When Ursula, Menace of the Deep enters, create Floatsom, a legendary black Eel token and create
Jetsom, a legendary black Eel token with,
"Sacrifice this creature to have target creature
become a 1/1 white Human with no abilities."
Sacrifice a non-token creature, the next instance or sorcery spell you control cost {1} less to cast for each creature sacrificed this turn. Use this ability only once per turn.