Ed and Rys, Inseparable

Whenever you cast a Dog spell, create a 1/1 green Cat creature token.
Whenever you cast a Cat spell, create a 1/1 white Dog creature token.
{r}{g}{w}{t}, Ed and Rys, Inseparable deals damage to any target equal to the number
of Dogs you control. You gain life equal to
the number of Cats you control.