Office & Coworker Magic Mug

Coworker mugs that hide the joke until the kettle has boiled. Black while cold, revealing as the coffee goes in — which is the difference between a gift that stays on a desk and one that quietly goes home in a bag.

How a colour-changing mug works

Cold, the mug is black and gives nothing away. Pour something hot in and the coating turns clear over about ten seconds, revealing the design underneath. Let it cool and it disappears again. It is a thermochromic glaze rather than a printed trick, so the reveal on the five hundredth cup is the same as the first.

Why it works as a desk gift

An office gift has to clear a low bar and a high one at once: funny enough to be worth giving, safe enough for a shared kitchen. A design that only appears while the mug is in use does both. Cold on the shelf it says nothing at all.

Suits a leaving do, a secret santa, a promotion, or the colleague who carried the quarter and knows it.

Care and specifics

• 11 oz ceramic, black when cold, revealing when hot
• Thermochromic coating — the effect does not fade with washing
• Hand wash only; not microwave safe
• Printed to order and shipped free in 2–7 business days

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