Daddy

Using his kids, Santa decided to include his father, Bobby, into the fun, not through hypnosis but through body and mind alterations. Instead of being a hunk with a dad bod and a bit of hair, Bobby became a wasp-waist futa with unnatural figures, a massive cock, blonde hair, big lips, shiny skin, long legs, a body at 9ft tall (standing over Santa's tall and amazonian mom), slight yet clear bimbo energy, and a submissive personality when it comes to interacting with Santa. Once the job was finished, Santa included his neglected father in their fun, fucking Bobby while she impaled Abby on her cock, and other such variations.

Bobby and Santa ended up developing a stronger bond than ever, often competing to see who'd impregnate the ladies first. The first wave in the family was Santa's, but afterwards, Bobby either scored some women who became pregnant before Santa could impregnate them, or Santa's sperm ended up impregnation them after Santa had already impregnated them, usually by impregnating the foetus or instinctually luring out eggs. For the women not involved with Santa, Bobby went to town, going on a large sexual campaign where all the women Bobby didn't think Santa would like would be brutally impregnated into their very ovaries, making them birth dozens of babies every menstrual cycle due to all the eggs in the ovaries getting fertilised.