From Copilot Ai:

"a spark when unplugging can mean something is wrong with the outlet, especially if the spark is large, colored, repeated, or accompanied by heat, odor, or noise. A tiny blue flash is normal; anything more is not."

A tiny spark, blue or sometimes yellow, is normal when unplugging something that is pulling current (i.e. working) while unplugging it. You are more likely to experience it with devices that use lots of power, like toasters, space heaters or electric kettles. The size of the spark will also be somewhat proportional to the speed at which you pull the plug; the faster you pull on the plug the smaller the spark will be.