A friend recently discovered a very strange plant growing in their garden. It seemed utterly alien. They used an online visual tool to identify it. It turns out it's something called "horsetail" and it's considered a "living fossil". (In its later stages of life it does look much more plant-like).

Via wiki:

> Equisetum is the only living genus in Equisetaceae, a family of vascular plants that reproduce by spores rather than seeds.

> Equisetum is a "living fossil", the only living genus of the entire subclass Equisetidae, which for over 100 million years was much more diverse and dominated the understorey of late Paleozoic forests. Some equisetids were large trees reaching to 30 m (98 ft) tall.

https://en.wikipedia.org/wiki/Equisetum

The plants that we see right now are just a snapshot of what's currently successful. If we eventually find alien life somewhere, the strangeness might look a lot like the earth-bound "aliens" of our own past.