A phrase used by drama-prone, annoying teenage girls to describe birthday wishes from Facebook friends with whom they do not regularly interact.
Annoying girl: "ZOMG! I got so much creeper cake on my birthday!!!!!!!1111! So many creepers on my profile!!!!!1111!!
Everyone else: "People don't have to creep your profile to see that it's your birthday. If you're on their list, it pops up in their feed. They say 'Happy Birthday' and move on with their lives. Get over yourself, you annoying bitch."
Creeper Cake is served when a Facebook creeper gives birthday wishes to every single one of his/her facebook friends on their birthdays.
This kind of creeper uses Facebook simply as a matter of wishing others happy birthday, despite the fact that they have never spoken to any of his/her Facebook friends in real life.
When this kind of creeper wishes someone a happy birthday on Facebook, it is known as Creeper Cake.
"How many birthday wishes did you get on Facebook?"
"I don't know, but I got tons of Creeper Cake from people I don't even know"
"That Becky girl is such a Facebook creep. She loves giving out Creeper Cake to everyone on their birthdays"