Chaos' Bite is very similar to Frostbitten. The effects looks the same except for the icon. Chaos' Bite deals 20% of the target's Max Health Chaos Damage that ignores shields and damage reduction. The debuff also is not affected by the immunity of Frostbite Immune. Chaos Damage Reduction can mitigate the damage. A high Skill stat of the attacker can increase the percentage.
The following heroes have or can inflict/apply Chaos' Bite:
Cold Summons (Special Attack): Summons a horde of Ice Golems who attack each enemy for [??%] Melee Physical base damage and chance to add Chaos' Bite debuff. Revives any allied Dragons, then replaces dead allies with Ice Golems. Chaos Day modification: powers up minions.