Calvin & Hobbes, 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}: Calvin & Hobbes, 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.