The Flaming Hoop is a special type of object in Fortnite Battle Royale.
Related to one or more challenges.
You have to jump through 5 Flaming Hoops in the Season 5 weekly challenge: "Jump through flaming hoops with a Shopping Cart or ATK".
Flaming Hoops can be found in several locations around the map.
See map below for the locations of all Flaming Hoops.
Flaming Hoops Locations