I use a 260 plus an undipped 321, both in black. Put four 4" bends in the 260, then two ear twists, and end with four more 4" bends; drain and tie-off. This will be the wingspan.
With the 321, inflate less two inches or so. At the nozzle twist off a two inch ball and then split it into two bat ears. Twist off a four inch bat head and twist in the two ear twists of the wing, one front and one in the back.
I use a white pen to frame eyes a la spiderman-shape with red eyeballs plus the mouth/teeth. End w a bit of shaping for the body. Can be carried or easily mounted on a hat.
With a white 321 and using the 260 to add hands, you have a quick ghost too.