A custom optical illusion to add to your selfie stick.
To reduce vainglory and self-importance, victorious Generals in Ancient Rome would receive Memento Mori: a constant reminder of the fleeting nature of celebrity and acclaim, and that "Thou art mortal."
Derided as "solipsistick" and the epitome of narcissism, perhaps the Selfie Stick needs an accessory to rein in runaway vainglory. Or maybe just a way to add emoji to your selfies.
Using principles of anamorphosis—obliquely distorted perspective—the printed graphics are applied to the selfie stick. The smartphone camera is the only vantage point capable of decoding the image, inserting a graphic into your selfie. Perhaps it's a sober reminder of your mortality in the midst of your vainglory, or simply a pile of poop with eyes.