Nalada, Snowicidal Maniac

: Whenever a Snow-Covered land enters or leaves the battlefield or becomes tapped, Nalada deals 3 damage to that lands controller.
: Whenever a player is dealt damage, if they've been dealt at least seven damage this turn, destroy target Snow-Covered land they control.
-2: Nalada deals 1 damage to target player for each Snow-Covered land they control. If he deals at least four damage this way, destroy target land.