If you grow enough seedlings, there will be some weird ones over the years. Here's two from last year - a siamese twin on one of Paddymac's F2 blue variegated Tiger seedlings:
and an F6 Spanish Spice pepper that I thought was a quadcot, but the stem is so broad that it might also be a twin:
I can't say what happened to them, as I likely planted them out along with all the others and lost track of their differences as they aged and the dominant side put out branches like any normal plant.