spinda's form

3 is with Entei, 8 was with Raikou.

It changes every month

The Pokemon Go pokedex has a measly 8 possible forms listed. Last month was the form #8 with research "Make 3 curveball throws in a row." This month is form #3 with research "Make a great curveball throw."

Hmmmm, I didn't know this. I completely missed form #8. Oh well. I didn't even know it was a thing until I got one last week.