My son has woken up periodically crying about his legs feeling like jello and he can t walk. He usually has a slight red face which looks like he may have a fever. When I touch his forehead, he doesn t feel hot. When this happens, he wants an ice cold drink of water and then ends up sleeping for hours. As a side-note, he always sleeps very hot and wants to sleep in shorts even when it s winter. I m not sure if this has any link to the jello legs.