In honor to FIFA World Cup Russia 2018
Defeat the Stormball Troll (random spawn) in any Scaling Normal Dungeon in any difficulty except Normal or in an Event Dungeon of any difficulty, and get Stormball Costumes and Emotes.
Collect them and add them to Collector's Bag and you can get Giant Stormball Mount.
If you have not luck with the drops, you can buy any Costume or Emote from the shop.
You can buy them with andermant from the Shop (T) OR you can buy them with gold from the Premium Merchant Emilia if you have Premium.
Note: Costumes and emotes are available to buy in shop only when a match is on. For example, when the match Croatia-England was on, you could buy the costumes and emotes of these two countries.