If you don't cast it without paying its mana cost but rather cast it later in the turn, you must pay its costs, and you must follow all applicable timing rules
The biggest reason to play this card in Historic
Like Memnite in the Tempered Steel deck of its age, Rootwalla intersected with the rest of the Blue-Green Madness Standard deck to be an actual threat, saving your Wild Mongrel from a removal spell and putting another body on the board
Its nice to see Hei Bai, Forest Guardian give Go-Shintai some competition, but Ive already outlined why I think its worse as a shrine commander
I have no idea why it commands so little respect and attention, the thing is pretty terrifying and relentless
This 3/5 has flying and whenever an opponent draws a card except the first one they draw in each of their draw steps, you get to create a 1/1 green Snake token