The Hati cloak is an item obtainable by killing Hati in the all winter events since 2012. This item is purely cosmetic and does not yield any bonuses at all. However, if you possessed Hati paws from previous years, energy would flow from the cloak and recharge them. This also works if you don't have them in your inventory or have even destroyed it. When you reclaim the paws from the Fremennik citizen it would be fully charged.