The Ediacarans, creatures that lived in Earth’s oceans half a billion years ago, left behind fossils that look like nothing alive today. Now, using an ice cube shaped like Star Wars’s Death Star, scientists have found that the impressions they left behind may be those of internal “skeletons” and not of the creatures themselves, Cosmos magazine reports. Researchers froze a piece of corrugated cardboard inside a Death Star–shaped ice cube and placed it in the same kind of sediment that surrounded many Ediacaran fossils. Then, they let it melt—imitating the decomposition of soft tissue. They found that the shifting sediment preserved the pattern of the internal cardboard “skeleton,” but not the Death Star shape surrounding it, they report this week in Nature Ecology & Evolution. That suggests, they write, that the traces Ediacarans left behind are likely from their insides, not their outsides.