Where can I get your freezer? Damn near amazing if it freezes gas. The ice cube would melt, the flame doesn't heat it up quickly enough to ignite it from frozen. Depends on what you throw it at, but for the majority of the time, and most surfaces you would throw it at, nothing's going to happen, except people might look at you oddly for throwing dirty ice cubes at a wall. But of course if you threw it at a surface made of highly reactive molecules, which spark when anything is done to them, I guess it could go boom.