Techie-Made Metatronic Generators
One-off or limited use items are de rigueur for the various fiction sources that inspired Monster Hunters and very much in-genre for games featuring aliens and heroic scientists. To simulate the former, simply use the "One-Time Use" modifier which reduces the final cost by 1/5, the latter requires a but more work. First, define what "limited use" means. If it means you can only have a set number of generators at any one time, then the optional rules from the box When Standing Waist Deep in Gasoline, Avoid Matches (Pyramid #3/46: Weird Science, p. 20) are perfect. What if it means that the device itself is fragile? Such inherently limited gear would require Temporary Disadvantage, Maintenance. Represent a lower starting HT (all generators begin with a HT of 12) as a -0.5 CF per -1 to HT. This is incompatible with the Rugged or Resilient options. If every breakdown requires a major repair, treat this as a Nuisance Effect worth -10%. Optionally, if the device is utterly destroyed after a single use (normally, even one-use device can be scrounged for parts), add "Backlash, Destruction, -300%" to offset the cost.
For rules to actually create the device, see GURPS Monster Hunters 2: The Mission (pp. 24-25). Simply compare the final cost of the generator with the list found there and go to town.
Example of Techie Metatronic Generator Creation
Eddy and his team are trapped in a warehouse by a group of humans who have been fully taken over by cybercytes. They're low on ammo, have no way of communicating with their home base, and their technomage has been infected and unless he can get treatment and soon he'll become their enemy. Eddy has little to work with in the warehouse, but he's done more with less. Eddy's player decides he's going to build a one-shot electromagnetic pulse "bomb." The GM rules this is either a type of affliction limited to those with the Electrical disadvantage or an Innate Attack with the Surge modifier. Eddy's player chooses the latter. Since the design he has in mind is going to cost $10,000 to build, it'll take 1dx20 minutes and give a -1 to skill rolls. The GM rules that the components for the EMP bomb are easy enough to find and rules that the warehouse has what is needed. Eddy rolls a 1 for the time required, but deems 20 minutes too long and takes a -9 to his skill to assemble the device in only 2 minutes. With a skill of 21 and a -10 to his roll, Eddy succeeds on a roll of 7 and his latest invention: the Cyber-Splinter Bomb is made. Because he didn't have time to properly shield the circuits he built in a limitation that makes it totally unusable afterward - but this doesn't matter as long as they can get away from the cybercyte-men.
A large device the size of a thick textbook that's essentially a very large and very powerful one use battery. Activating the bomb requires a full minute as it charges up, after that it can be triggered and results in all machines within a 32 yard radius taking 8d burning damage with the surge modifier. All those who take damage must make a HT roll at -1 per two points of penetrating damage. Failure results in them being stunned and may make a HT roll with a penalty equal to the original penalty to recover. This is a one use device and its components cannot be reused for another similiar device! It's a hunk of useless metal and fried circuit boards. Small, $10,000, 3 lbs. XS or 2xB. LC2.
Statistics: Burning 8d (Accessibility, Only those with the Electrical disadvantage, -20%; Area Effect, 32 yards, +250%; Backlash, Destruction, -300%; Emanation, -20%; Side Effect, Stunning, +50%, Surge, +20%; Superscience, -10%; Weakened Without Immediate Preparation, -20%) .