I have an almost unlimited source of potential objects I can melt in my house. I have two kids and they have too many toys, most made of plastic, so I foresee an endless source of entertainment with potential of registering some really cool effects.
In this video I heat up a little plastic dinosaur. The material burns quicker than it melts. So in the first half of the video I pretty much have just a blackened crust covering it. That is until the material underneath starts bubbling and then burning. Because a hard crust forms around the boiling plastic, it expands, giving the appearance it is growing uncontrollably.
This is a very cool result and I believe you will enjoy watching it.