Chris and Aliyah, Inseparable

Whenever you cast a Dog spell, create a 1/1 Green Cat token.
Whenever you cast a Cat spell, create a 1/1 White Dog token.
{r}{g}{w},{t} Chris and Aliyah, 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.