Glalie and Regice don't do much but stack weaknesses, so replace them with Mamoswine to cover rock, fire, and steel and black Kyurem to hit stuff really hard. Give Abomasnow a mega stone and 252 HP/4 Atk/252 SpA quiet for better special attack. Replace its rock slide with ice shard to hit faster opponents. Give Froslass cursed body to possibly disable attacks, a focus sash to guarantee that it survives one hit, and 4 HP/252 SpA/252 Spe timid to maximize speed. Replace reflect, aurora veil, and draining kiss with spikes to lay hazards, taunt to stop other hazard users, and shadow ball for more power. Give Avalugg a rocky helmet to hit most physical attackers and 252 HP/252 Def/4 SpD relaxed to maximize physical defense. Replace rock slide and gyro ball with roar to reset stat boosts and toxic to defeat defensive opponents. Give Lapras water absorb to better switch into water attacks, and give it choice specs and 4 Def/252 SpA/252 Spe modest for more power. Replace its moves with freeze-dry to cover water, fire hidden power to cover ice and steel, surf to reliably hit opponents, and hydro pump to defeat certain threats more quickly.
