This heart looks like a normal conversation heart, but it’s really just a collection of bubbles. (After several hours in water, the sugar has dissolved away, leaving only colored gelatin and air bubbles). Piercing it with a pin is easier than poking a marshmallow.
For more fun Valentine's Day candy experiments, try these:
Peel the words off of Jelly Belly beans
Sinking Hearts with Cakemate candies
Hearts bobbing in soda
Hearts bobbing video
Hearts expanding after a soda bath
Hearts fading in sunlight