I think you're talking about a "dill pickle" stone. Planets have different themes, and some of them are very unique. I know many people who really anticipated getting a dill pickle planet. Wait until you see a square planet! You don't get those as a theme, but you will find them sometimes in space. I will see if I have a list of the starter planet themes. You don't get a theme planet every time.
The ones I remember best off the top of my head are dill pickles and tentacles. Now those are WEIRD.
I have a ton of old documentation from discussions, but since it can be ten or more years old, and is in all kinds of arcane one note formats, it's sometimes hard for me to find.
List of planet types (I'll update as I remember them)
Balancing Rocks (These are tower and also shorter rocks balanced on each other)