cryo-aliens colonizing snowball earth

kinda popped into my head this morning 🌿🚬😌💨. during earth's period of global glaciation a species from an ice planet colonize earth, they were a space faring people whose world was increasingly small and full of strife. they found mycelial life that they could use that was never preserved in the fossil record, and they were able to plant their own planet's vegetation, also too soft to be preserved in the fossil record. living largely on ice shelves, any evidence of their existence has been at the bottom of the ocean for hundreds of millions of years. they have rebuilt their own civilization from their own planetary disaster and now return to earth with claims that they were here first and an offer to exchange lands in polar regions for climate cooling technology 👽🛸👾🖖🏻