In the end, I didn't add bats to that sketchbook piece, but I did draw this, using charcoal pencil and normal HB pencil, to get an idea of how the painting might look:
So, using the above sketch and my previous moon painting as inspiration,
I painted this piece, Batty Moon, using acrylics, silvery poster paint, liquid watercolour and blue glitter glue. It depicts a cloud of bats, silhouetted against a bright full moon, in a dark blue night sky:
The dark colours of the sky continue over the sides of the canvas on which this is painted, as do the shimmer of the blue glitter and the bat detail, to give one continuous block of colour. This means that this piece does not need to be framed. This square box canvas measures 15cm square by just under 4cm deep.
Find it for sale here.