Boreal Spider

Ice/Snow Walk: The spider can walk and climb across snow and icy terrains without difficulty and doesn't cost extra movement 

Snow Camouflage:  The spider has advantage on Dexterity (Stealth) checks made to hide in snowy terrain 

Spider Climb: The spider can climb difficult surfaces, including upside down on ceilings, without making a skill check

Cone of Cold:  The spider blasts a creature with cold air from its eyes. Each creature within the 60 ft cone must make a CON save. If failed, the creature(s) takes 8d8 cold damage, half of that on a save. If the creature drops to 0 HP from this spell, the creature becomes a frozen statue until it is thawed out 

Bite: Melee Weapon Attack: +6 to hit, reach 5ft, one target. Hit: 8 (1d10+3) piercing damage, and the creature must make a DC 12 CON save. If failed, the target takes 18 (4d8) cold damage, and 9 (2d8) poison damage. Half damage on a save. If the cold damage reduces the target to 0 HP, the targets becomes frozen. The target can be thawed by spending 1 hour in warm temperatures or takes 15 fire damage. If the target is reduced to 0 HP from poison, the target is stable, but poisoned for 1 hour, even after regaining hit points, and is paralyzed. 

Web (5-6 Recharge): Ranged Weapon Attack: +5 to hit, range 30/60 ft, one target. Hit: The target is restrained by webs. The restrained target takes 7 (2d6) cold damage per turn it is restrained in webs. Target can make a DC 14 Strength check, bursting the webs on a success. The webbing can be attacked and destroyed (AC 12, HP 7, vulnerability to fire damage; immunity to cold, poison, bludgeoning, and psychic damage.) 

Ambush:  The spider bursts out of its snowy burrow when a creature gets within 10 feet of it