I have Pandora's box and the key, how do I open the box?

You don’t need to perform any action to open Pandora’s Box.

Once you own both items, the effect is automatically activated during your run.

You’ll notice a blue aura surrounding your hero — this indicates that Pandora’s Box is active.

Try letting enemies step inside that aura and watch what happens!

The attached video shows the effect in action, but the best experience is to discover it directly in-game.