This is a 3D printed adaptation of Cardboard Man props & DIY's Batarang:
https://youtu.be/wn64lckTs9Q

For assembly follow the video. For this adaptation, I replaced the stick and round cap with a screw and nut as well as the caps for threaded ones so it can be easily dismounted for any reason, however, the files are still available for printing.

3D printed Parts:
x1 WingA
x1 WingB
x2 ring
x1 Cap_nut
x1 Cap_Screw_head
x2 Cap (for version in video)
x1 stick_cap(for version in video)

Other materials:
x2 magnets 1cm diameter 2mm tall (or any you have, just modify the files on meshmixer or any alike software)
x1 M3x20 screw
x1 M3 nut
x1 pen spring (I cut it to be about 1cm tall)
Superglue

Following each image below:
1 All materials for this version.
2 Glue the rings (ring.stl) to both wings (WingA.slt, WingB.stl)
3 get the screw into the spring and glue or fit press the magnets in place (beware of polarity since they have to stick together when the Batarang is folded)
4 Join both wings as shown
5 Pass the screw across the wings
6 tight the other end with the nut
7 Screw the caps following their name (Cap_nut for the nut end and Cap_screw_head for the screw head end)
8 This design (right) is thinner than the original (left) and uses removable caps

With a flick of the wrist unfold your Batarang!
Be the BATMAN