What Does Mystery Key Do in Undertale?

Best Answer

The Mystery Key unlocks the house next to Napstablook's in Waterfall. Inside, you'll find a lot of unique lore about Mettaton!

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More Answers

CarryingTree·3 months ago

Really, it's just for some neat background info and a bit of fun exploration. Don't expect epic loot or anything.

WanderingFacet·3 months ago

It opens Mettaton's house, giving you some extra bits of the story. Totally worth using if you're into the lore and backstories.

RemovingMyth·3 months ago

You use the Mystery Key to open the house to the right of Napstablook’s house in Waterfall. You’ll learn cool stuff about Mettaton!

👀 If you like Undertale...

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