A color changing mug is a type of mug that changes its color when it comes into contact with a hot liquid. The surface of the mug is coated with a special heat-sensitive material that responds to changes in temperature.

When the mug is filled with a cold liquid, the material is in its "resting" state, which may be a plain, dark color. However, as hot liquid is poured into the mug, the material changes its state and reveals a new color or pattern. The change in color is usually temporary and reversible, and the mug will return to its original color once it cools down.

This can be a fun way to add a little extra interest to your morning coffee or tea, and they can also make great gifts for friends and family members who enjoy hot beverages.

It's important to note that color changing mugs are not microwave safe and should only be hand washed. Using a dishwasher or microwave could damage the heat-sensitive material and cause it to stop working. To keep your color changing mug looking its best, gently wash it with warm water and soap and avoid scrubbing the surface too hard.