Shrewd Hatchling

“Shrewd Hatchling enters the battlefield with four -1/-1 counters on it. <br> (U/R): Target creature can't block Shrewd Hatchling this turn. <br> Whenever you cast a blue spell, remove a -1/-1 counter from Shrewd Hatchling. <br> Whenever you cast a red spell, remove a -1/-1 counter from Shrewd Hatchling.”