A possible plot twist is that the curse is slowly changing Sam's nature. Since he's pregnant under the curse, he might start to develop strange powers or behaviors. For instance, he could be more empathetic towards the monsters they usually hunt, which would be a huge shift in his character. This could be part of the curse's plan to disrupt the balance in the Supernatural universe. And the only way to break the curse might be to sacrifice something very dear to Sam, like his connection to his family or his hunting skills.
One common plot twist could be that the curse is related to a powerful supernatural entity that wants to use Sam's unborn child for some dark purpose. Maybe it's a demon who plans to possess the baby as soon as it's born. Another could be that the pregnancy is a false one, created by the curse to deceive Sam and his friends into believing he's carrying a child, when in fact it's a trap to lure them into a dangerous situation. For example, it could be a spell by a witch to get revenge on Sam for something he did in the past.
A common plot twist could be that the pregnancy is not as straightforward as it seems. Maybe there are health complications for Leah or the baby that throws their whole plan into chaos. Another could be that there is some mystery about the baby's true nature, like it having some special powers or being part of a prophecy in the fanfiction world.
One possible plot twist could be that they discover the pregnancy is high - risk due to some genetic factor. This would add a lot of drama and worry to their relationship. They might have to make difficult decisions about medical treatments or lifestyle changes.
It adds a whole new layer of drama. Sam's situation forces the characters around him to make difficult decisions. His friends have to decide whether to help him keep the baby or find a way to end the pregnancy to stop the curse. It also creates internal conflict for Sam. He has to deal with the physical and emotional changes of being pregnant while also trying to figure out how to break the curse.
Maybe a plot twist could be that Sam's transformation into a kid is part of a larger, more sinister plan by an unknown entity. This entity could be using Sam as a child to manipulate Dean in some way, perhaps by making Dean over - protective and leading him into a trap.
One common theme is the struggle for acceptance. Sam might struggle to accept the situation himself, and his friends may have a hard time accepting it too. Another theme could be protection. Sam would likely feel the need to protect Ruby and the unborn child in a world full of danger. And there's also the theme of change, as this situation would drastically change the lives of both Sam and Ruby.
One common plot twist could be that the pregnancy is part of a Capitol plot. Maybe they were somehow manipulated into it to create chaos or control. Another could be that one of them has a hidden illness that threatens the pregnancy and their relationship.
Often, a plot twist might involve the nature of the baby. In some fanfictions, the baby could have powers that are not just a combination of vampire and human, but something entirely new. It could be a power that is so strong it attracts other supernatural beings, not just vampires. This would change the dynamics as Bella and Edward would have to protect the baby from new threats.
One common plot twist could be that Caroline discovers she has a hidden power related to the Supernatural world. Maybe she can communicate with spirits in a unique way that no one expected. Another could be that her sister, who she thought was normal, is actually part of a secret Supernatural society. This revelation would turn their relationship upside down and lead to a whole new set of adventures and challenges.
A plot twist could be that the daughter of hell has a twin sister who is the complete opposite of her. While she is trying to find her place between good and evil, her sister is causing chaos. And it turns out that their fates are intertwined. Another might be that she loses her hellish powers but gains a new, unexpected power that is related to something in the human world, like the power of human love or hope, which then sets her on a new path that no one, including herself, could have predicted.
One common theme is the challenges they face as a couple with a pregnancy. It could be about how they deal with the military regulations in the Stargate universe while expecting a child.