Ice-erang

In Australia there is a well known traditional Aboriginal weapon called a boomerang. This works perfectly well, but as always modern means of production can bring improvements.

In this case that improvement is the Ice-erang.

The Ice-erang is a boomerang made entirely from ice. It comes out of its two part mould perfectly formed and aerodynamically ready for throwing, and there is no need to worry about catching it on its return journey or retrieving it. If it goes astray, it will quickly melt away, and probably won't last more than one throw anyway in the scorching heat of an Australian outback location.

Once you have dispatched one Ice-erang, simply pop out another one from the dozens you have pre-made, and stored in your cold box ready to launch.