In a dimension where unbirth and recursive pregnancies are all the rage something new came from it. After someone who was unbirthed came back out still in their amniotic sac which then sparked interested from people seeing the potential of the whole idea and soon after people in large amniotic sacs became a common sight like the other big two with them enjoying their new lifestyles of being cushioned and floating around in their amniotic fluid. Yet with every pro there's a con and the sacs were no exception due to the person inside depending on the sac and it's umbilical cord for nutrients along with depending on others to roll their sacs around due to them losing their mobility but if ruptured their at risk of dying or killed instantly if popped. But that doesn't stop people from being those big round jelly sacs including people like you.