Bonus chests are on Treasure Hunter. From 00:00 UTC (game time) on 6th August until 23:59 UTC on 10th August, you can charge them up, see what's inside, then open them for twice the loot of a regular chest!
How do Bonus Chests Work?
Head to Treasure Hunter and you'll be able to open up the new bonus chest right away, and claim two prismatic lamps.
After that, each time you use a Key to open a normal chest, you’ll add one charge to the bonus chest. You can see what's inside the bonus chest by hovering your mouse over it, and its contents will change with each Key you use.
Once it reaches five charges, you're free to open it and claim its contents – which will be twice the amount of a normal Treasure Hunter prize! That includes everything – right up to the most sought-after items Alice has to offer.
Note that you can charge the chest up to ten times, and opening it will consume five of those charges. The prize will continue to change, even if you continue using Keys while the bonus chest is at the full ten charges.
If your doubled-up prize is a unique item – a skilling outfit piece, for example – you will receive the duplicate's cash-out value in its place.