From the Publisher's web site:

This is the fourth expansion to the popular Beer & Pretzel’s Game Starfight. This expansion features a mighty doomsday machine called the Death Cube. This is not a game itself, you need the Starfight© base rules and the expansions II and III in order to use this expansion.

This PDF contains:
•A rulesheet
•A Death Cube sheet
•A Death Cube counter
•A Death Cube screen

The Death Cube must be faced by four ships and it features a new weapon: the assimilation ray!

Beware, You'll need even more dice!

Expands:

• Starfight