Mail Order Monsters is a create-your-own monster game in which you start with a modest sum of money with which to purchase and outfit a fighting beast (or dinosaur... or blob... or even a regular old human).
Additional options include things like gills, tentacles, and photosynthetic skin in addition to more mundane items like laser guns and claws.
From the back of the box:
12 Different Monster Stocks, 20 Enhancements. All our monster stocks are upgradable so they can grow with your budget and ambitions. And you may select among 11 different enhancements for each basic stock - hands, tentacles, fangs, fiery breath, resistance to specific attacks - a total of 20 in all. Custom order your monster to match your own specific tastes and style, then show it and use it with pride and confidence.
15 Weapons, 6 Defenses, 9 Additional Choices. Nothing complements a good choice of basic traits and extras like a trip to our weapons department. Each selection is state-of-the-art, from the U.S. Marine issue grenades to this year's breakthrough innovations in lasers and psionic amplifiers. And every item in the catalog carries the full Mail Order Monsters guarantee against battlefield breakdowns.
8 Exotic Battlefields. Test your monster's mettle against an elite corps trained and maintained by computer or against the monsters of other proud owners like yourself. We handle transportation and cleanup, and see that the winner is rewarded with psychrons for its owner, comfortable quarters in our spacious corrals and the right to make another trip to the weapons shop or the enhancement vats.