Odd shape egg

Something weird happened in the shell gland while the chicken was laying the egg. Usually I get odd shaped eggs similar to this when my girls are under stress, they had something scary happen while the egg was in the shell-application portion of their egg making system. Older hens can also be more prone to lay these. But it could just be a one-off. No need to worry. Also, I don't think there's a way to fix it if they make a habit of it, if it's too weird I feed the egg back to the chickens.