Emily the Strange from Cosmic Debris Etc, Inc.
You can see the image I selected to recreate in latex in the lower left corner of the first picture. Above is a (inverted for no particular reason) copy I printed onto a piece of adhesive label.
You also need some latex leftovers in black (0.25mm here), red (0.4mm) and white (0.4mm; not shown on the picture) and some cutting tools of your choice.
I repeated the process with the red piece of latex, where I cut out the slingshot and the small ball. Because the red parts are later glued behind the black parts, there is no need to cut the the inner contours of the slingshot (see third picture).
As a last step I glued the black/red piece onto a small sheet of white latex.
Normally I would clean both parts with thinner and also apply latex milk onto both parts before I let them dry and put them together. For the creation of decals it is sufficient to apply the latex milk to only one part (here the black one) so you do not need to remove the glue from the other one (the red and white ones) later.
On the last picture you can see the final work lying on a black background. I have talced the decal to preserve it until later (you might notice the matt look and the talcum powder in particular within the slingshot contours). I will show you a polished version later.
Caveat: you will notice that my contour lines are not as thin as the original ones. The reasons are, that on the one hand I might have been too anxious of cutting the contours too thin and spoiling my work. On the other hand the "melting" with thinner also added some width to the contours.