I love this bat. The model is by Anna Kastlunger, and the diagram can be downloaded.
I love that it is simple-looking, yet very recognizable.
It is folded from 35cm double-sided kami.
I was at a science-fiction convention last week-end, and distributed a huge bag of origami – people called me the origami faerie, it made me very happy to see the paper joy spead! The person who took this one seemed to have fallen in love with the model :)
These adorable bats are very, very popular among all the people I give my origami to. I fold them regularly, because I know people will always be happy to have one – I think it’s partly because of the magic of pop-ups, but they’re also particularly beautiful.
The bat on the right is folded with 24cm double-sided paper. The bat in the middle is from Tuttle Rainbow patterns 15cm. I don’t remember the leftmost paper.
You can find the (beautifully hand-drawned) diagram in “Origami Pop-Ups to Amuse and Amaze” (ISBN 978-1494299026). He also made a youtube video.