Microwaving a watermelon can have potentially hazardous consequences, and I strongly advise against attempting it. Microwaves heat food by agitating water molecules within the food, causing them to vibrate and generate heat. Watermelons, being mostly composed of water, contain a high moisture content.
When a watermelon is subjected to the intense heat of a microwave, the moisture inside can rapidly heat up and turn into steam. The steam buildup can cause the watermelon to burst or explode, resulting in a messy and dangerous situation. The forceful release of steam and the potential scattering of hot watermelon pulp can cause burns and damage to the microwave.
Microwaving a watermelon is not a safe or recommended cooking method. If you want to enjoy a warm or cooked watermelon, it is best to explore other cooking techniques such as grilling, baking, or using it as an ingredient in various recipes.