Step 1: Your best friend (lesbian in this case) gets engaged to a yandere.
Step 2: Your best friend and her fiancee stay at your place the night before your 10-year high school reunion.
Step 3: Yandere makes up some excuse to go home early so you don't get to hang out with your best friend the next day.
Step 4: You don't realize your best friend's fiancee is a yandere until you ask your best friend to be your maid of honor.
Step 5: The yandere sends you nasty messages on Facebook.
Step 6: You ask friends and family for help.
Step 7: Friends and family tell you not to respond to yandere's messages, so you just don't say anything at all.
Step 8: Yandere blocks you on Facebook, and your best friend unfriends you.
Step 9: You keep watching both the Yandere and your best friend through your pen name account.
Step 10: You wait and pray, but try not to dwell on it too much since you're getting married soon.
Step 11: You have a wonderful wedding, and another friend flies halfway around the world to be your maid of honor.
Step 12: You see wedding photos of your best friend and the yandere. It's a small courthouse deal. You feel a little smug that your wedding was better than theirs.
Step 13: It looks like things are going poorly in your best friend's marriage. Your best friend posts this song as a cry for help:
Step 14: You ask your mom to reach out and talk to your best friend since your mom and best friend are still Facebook friends.
Step 15: Mom and best friend have a long phone call.
Step 16: Mom reminds your best friend that you still care.
Step 17: Mom tells you that the yandere has dissociative identity disorder and probably bipolar disorder too.
Step 18: Your best friend finally decides to call you and spills all the horrifying details.
Step 19: Your best friend gets exhausted trying to make the marriage work.
Step 20: Local laws mean your best friend can't file for divorce for a whole year.
Step 21: Your best friend goes back and forth about trying to make the marriage work.
Step 22: Your best friend finally gets to file the divorce papers.
Step 23: The pandemic starts.
Step 24: You have a video chat with your best friend and find out she's happy in a throuple now, but she can't see her girlfriends for a while due to the pandemic.
Lesson: Yanderes are real, and they are a nightmare.