Not so much a doodle as a piece of alien design on my part. A few years ago I explored the idea of creating a book for kids about how evolution works using plausible aliens and an alternative Earth. The late great Stephen Jay Gould once wrote that if the evolution of life on Earth was a tape, and we were somehow able to 'rewind' that tape, no matter how many times we replayed it humans would not appear. Nor would most of the life forms we know today. We owe the fact we exist to a million billion trillion gazillion tiny chance events and advantageous mutations. Anyhow, for various reasons, I never got around to doing it despite input from the likes of Professor Jack Cohen and Australian artist Alex Ries.
Here are two of my aliens in a size comparison chart with some Earth species, extinct and extant. It was an interesting challenge trying to mke them look both realistic and yet alien. It's a project I may return to one day. Here's a close up of one of my aliens: