It doesn't appear that the latex is in any way trying to attack or transform you. You hold it up to the streetlight and can see the shaft of ruby red glow that it emits. It looks really sharp, you would wear it if you could...
That gives you an idea. You turn around and carefully make your way home, jumping at every little sound and dodging every shadow. You really don't want those creatures following you. You eventually reach your house and go inside, locking all the doors and windows before putting it on your nightstand and going to sleep.
The next day, you turn on the news and see a report about several strange disappearances in your neighborhood the previous night. Considering yourself lucky, you grab the beautiful gem and head down to your local jeweler. The jeweler gives you a strange look and asks where you got such an unusual stone, but you like and make up one about finding it near a river. The jeweler puts it on top of a ring and for a small fee let's you keep it. As you walk out of the store, you hold up your concentrated latex ring and admire the way it sparkles in the sunlight.
You almost completely forget about the ring until late one night a few weeks later. You decide to go on a late-night jog and are running down the street when a man suddenly jumps out of a bush and points a knife at you, demanding money. As you panic and raise your hands in the air, you notice that your latex ring seems to be shaking, glowing, almost. You turn back to your would-be robber and see what happens next.