There are a couple of tasks that can cause confusion, so check carefully the instructions in the event.
Option 1: Win new World Map level with a specific fiend
The World Map Levels are the levels that you see when you first open Best Fiends. They’ve also been referred to as ‘story levels’, ‘main levels’ and ‘normal levels’.
If you are playing an event and are required to ‘beat World Map Levels with…’ then what you need to do is beat levels that you’ve not previously beaten with the named Fiend in your team.
To change the Fiends in your team, just tap on the level button and, before you make a match in the level, you’ll see the option to ‘change Fiends’. Tap on that button to see all available Fiends.
Option 2: Win new levels in a specific Fiend Quest.
For this task, you’ll need to win levels in that fiend’s Fiend Quest. You can find Fiend Quests in the Special Missions slider.
Option 3: Win Lootballoon levels
Note that Lug’s Lootballoon is a special game mode that you can find in the Special Missions slider.
Lug’s Lost Treasure event is one of the daily events, along with Baby Slug and Minutia’s Most Wanted, and has nothing to do with the Lootballoon, but can be confused with the event task due to the name.