This challenge is part of the Fortnite seasonal mission called Winterfest. It will ask you to search a total of two ice boxes. The term is a bit confusing, but these are the kinds of metal coolers that have replaced regular chests since Christmas morning. You can find them all over Apollo Island.
Map
You interact with the ice supply exactly as you would with normal chests. They only contain certain items, such as Fishes, Snowball Launcher or Sneaky Snowmen. You'll have to keep an eye out to spot them as they don't make any noise nor spark.
The best place to complete the challenge in record time is Dirty Docks' East Hangar — which has been transformed into an ice factory. This challenge will allow you to acquire the Polar Renegade spray.
We recommend the Team Rumble mode to achieve this challenge, especially during the week following its release. It'll reduce your chances of running into warring enemies as soon as you land.