Zygarde, Keeper of balance

{r/g}{r/g}{r/g}: Zygarde becomes a 3/3 Dog and gains
Menace.
{r/g}{r/g}{r/g}{r/g}{r/g}: If Zygarde is a Dog, it becomes a
5/5 Wurm and gains Trample.
{r/g}{r/g}{r/g}{r/g}{r/g}{r/g}{r/g}{r/g}: If Zygarde is a Wurm, it
becomes an 8/8 Giant, gains double strike, and
has "Whenever another creature attacks, put a
+1/+1 counter on Zygarde."