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Morphing Harry Potter Mug

This mug appears to have little secrets to hide, swearing to be up to no good. However, ready your wands and reveal the hidden design! Add hot liquid and watch as the Marauder’s Map is revealed as though you had said the words, “I solemnly swear I am up to no good.”

Harry Potter - Marauders Map - I Solemnly Swear – 16 oz Large Ceramic Morphing Mugs Heat Sensitive Clue Mug – Full image revealed when HOT liquid is added

$24.98  in stock
2 new from $23.99
1 used from $17.99
Free shipping
as of July 13, 2022 2:02 pm


  • Do you know Hogwarts as well as Moony, Wormtail, Padfoot and Prongs do? If you solemnly swear you are up to no good, then this 16 oz color changing mug is for you!
  • At room temperature, this mug appears to only have the Marauder's famous phrase and footprints. Add hot liquid to reveal their charmed map of Hogwarts! Mischief managed.
  • We didn't use the Doubling Charm on this product! Images are to show the mug’s design from left to right. This listing is for one (1) ceramic mug.
  • To preserve the mystical abilities of this mug, we recommend hand wash only. Not microwave safe.
  • Trend Setters Ltd. creates a variety of officially licensed products from your favorite fandoms as well as hundreds of original designs. This product was designed and printed in the USA.

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