Another idea is that Castiel's drunkenness causes him to lose his usual grace - filled composure and he starts to behave in a very un - angel - like manner. He could get into comical situations, like trying to dance at a local bar and attracting all kinds of strange looks. This could also lead to him making new, unexpected friends who help him in a future battle in an unorthodox way.
Perhaps Castiel, while drunk, stumbles upon a magical object that he misinterprets due to his inebriated state. He thinks it's something harmless but it actually has the power to open a portal to a dangerous alternate dimension. Sam and Dean then have to figure out how to close the portal while also dealing with a very confused and still tipsy Castiel.
One idea could be Castiel getting transported to the Harry Potter world. Maybe he tries to understand the magic there using his angelic knowledge. Another plot could involve Castiel teaming up with Harry Potter to fight a common dark force that is threatening both the wizarding world and the Supernatural world.
One interesting plot idea could be Castiel protecting Kelly from various supernatural threats as she is pregnant. Maybe they have to go on the run and hide in different places, leading to some heart - to - heart conversations between them about the future of the baby and their own fates.
One idea could be that Sakura finds drunk Sasuke in a forest. She tries to take him back home while he rambles about his past traumas. Another could be that at a party, drunk Sasuke confesses something unexpected to Sakura. For example, his true feelings about their relationship that he's been hiding.
Another plot could involve the drunk dragon trying to regain its honor. It was once a respected and noble creature but due to its drinking problem, it has lost the respect of the other dragons. So it embarks on a journey to prove itself again, all while struggling with its drunken tendencies.
One idea could be Naruto getting drunk and accidentally revealing his deepest insecurities to his friends. For example, he might admit how he sometimes feels like he's not good enough despite all his achievements. Another plot could involve Naruto getting drunk and having some wild, out - of - character adventures in the Hidden Leaf Village that lead to both comical and heartwarming situations.
One plot idea could be that the reader is a hunter who has lost their faith, and Castiel helps them regain it. He shows them the good in the supernatural world and that not all angels or other beings are bad. Along the way, they form a deep bond based on mutual understanding and respect.
One idea could be that Harry wakes up after a wild night out, not remembering getting married. His friends then start to piece together the events that led to it, like it was part of a magical prank gone wrong. Maybe there was a spell involved that made him think he was in a different situation when he said 'I do'.
He might be more open and affectionate with Sam and Dean. Usually reserved, the alcohol could make him more likely to give hugs or say things like 'You two are truly my best friends on Earth' in a slurred but sincere way.
One plot idea could be Ketch getting involved in a time - travel adventure within the Supernatural universe. He could go back in time and interact with the Winchester brothers at different points in their lives, changing the course of events in unexpected ways.
One plot idea could be that the Winchester brothers have to face a water - dwelling supernatural creature while on a boating trip. Maybe it's a mermaid - like being that lures sailors to their doom, and they have to figure out how to stop it without getting trapped in its watery lair.