I can tell you that hard-boiling an egg typically involves submerging the egg in boiling water and cooking it until it reaches the desired level of doneness.
Attempting to hard-boil an egg without water would likely lead to unsatisfactory results. Water is essential in the hard-boiling process as it helps to evenly distribute heat, ensuring the egg cooks thoroughly and prevents it from becoming too dry or overcooked.
If you're looking for alternative ways to cook eggs, you might consider options like frying, poaching, or baking. Each method has its unique characteristics and can produce delicious results when done correctly. However, hard-boiling an egg without water is not a recommended approach.