Rulings

• You can’t cast Blizzard Brawl unless you choose both a creature you control and one you don’t control as targets.2021-02-05
• Check whether you control three or more snow permanents as Blizzard Brawl is resolving to see if the target creature you control gets +1/+0 and gains indestructible. That creature will still fight even if it doesn’t get those bonuses.2021-02-05
• If either target is an illegal target as Blizzard Brawl tries to resolve, neither creature will fight and no damage will be dealt.2021-02-05
• If the creature you control is still a legal target as Blizzard Brawl tries to resolve but the target creature you don’t control isn’t, the creature you control will still get the bonuses until end of turn.2021-02-05
• Snow is a supertype, not a card type. It has no rules meaning or function by itself, but spells and abilities may refer to it.2021-02-05
• The {S} symbol is a generic mana symbol. It represents a cost that can be paid by one mana that was produced by a snow source. That mana can be any color or colorless.2021-02-05
• Snow isn’t a type of mana. If an effect says you may spend mana as though it were any type, you can’t pay for {S} using mana that wasn’t produced by a snow source.2021-02-05
• Some cards have additional effects for each {S} spent to cast them. You can cast these spells even if you don’t spend any snow mana to cast them; their additional effects simply won’t do anything.2021-02-05
• The Kaldheim set doesn’t have any cards with mana costs that include {S}, but some previous sets do. If an effect says such a spell costs {1} less to cast, that reduction doesn’t apply to any {S} costs. This is also true for activated abilities that include {S} in their activation costs and effects that reduce those costs.2021-02-05