Naga Painseer

Deathtouch
When Naga Painseer enters the battlefield, if {u} was spent to cast it, draw X cards, where X is equal to the number of life lost this turn. If {b} was spent to cast it, target opponent loses 2 life and discards a card. If {g} was spent to cast it, target opponent loses life equal to the number of creature they control.