I don't have a specific mutation to suggest, but rather a way for something to be bred. So I'm thinking a mutation can only be bred during a certain event, or maybe gets a boost to be bred during a certain event.

One example might be a head tilt boost during May. (I just saw someone's suggestion for a head tilt mut and it seemed pretty cool.) It would make sense because head tilts in animals can be caused by various trauma (I'm mostly thinking of rats rn tbh) and there's a lot of combat happening in May.

Another option may be in one of the more "mystical"events, like June or July or October, one or more mutations could become available to be bred because of all the weird happenings. Perhaps this could also open up some in-game rational behind more "fantasy" mutations like third eye?

Any comments and suggestions are highly appreciated!