King Tantalus began to develop a plan to fool the Gods he was going to invite, His plan was to kill his son and make a stew out of him so that if they ate the stew they would have eaten a human, something they would never do and so his plan was to attempt to blackmail the Gods for eating a human.
"YES, IT IS A FLAWLESS PLAN, AND I WOULD BE REMEMBERED AS THE PERSON WHO FOOLED THE GODS"
"Gods of Olympus, I offer you a meal at my castle for my gratitude towards you"
You're horrible, a true disgusting person. For your actions we will resurrect your son and banish you from your kingdom into eternal pain.
You are to leave now and we will punish you once we bring back your son and would have decided your consequences
King Tantalus was put into a place where there was only one food source but he would be unable to get that food due to his legs being useless, for that was his consequence, to starve.