Spelljamming Mine (Magic Explosive)

This is a techno-magical creation, a sphere of brass about 1-foot in diameter and weighing 55 pounds—about the right size to be fired from a typical, heavy catapult. It radiates an aura of evocation magic.
The spelljamming mine is a combination of mechanical engineering and wizardry. It is actually a sophisticated form of homing weapon, with a large explosive charge of smoke powder. It is enchanted in such a way that it detects the presence of a spelljamming helm within 1,000 feet, and moves toward the helm's “energy signature” at a speed of 3,000 yards per round-the same speed as a ship with SR 6 traveling at tactical speed. The mine has Maneuverability Class A. When it strikes the ship it is pursuing, the smoke powder charge detonates. This inflicts 3-18 points of damage to unprotected crew within 70 feet of the impact point (saving throw applicable) and 2-5 points of Hull Damage to the vessel hit, which must then save vs. fire or suffer an additional 1d4 points of fire damage per round. A spelljamming mine can only move for a total of four rounds. If it has not yet reached its target within that time, it detonates.
Before it can be used, a spelljamming mine must be armed. This is done by pressing a series of tiny studs on the mine's outer surface in a particular sequence. The device has a kind of “antitamper” system-if the wrong arming code is entered three times in a row, the mine detonates. So complex is the code that even a character who knows it has a chance of making a mistake. To successfully enter the code, the character must roll equal to or less than his or her Intelligence on 3d6. After the mine is successfully armed, it remains dormant for 2d8 rounds-hopefully long enough for the users to catapult it off their vessel and get more than 1,000' away. At the end of this dormancy period, it becomes active, and homes in on the first spelljamming vessel to approach it. Obviously, because of the variability of the dormancy period and the unpredictability of space combat, a spelljamming mine is a dangerous weapon to use in ship-to-ship dogfights.
Nobody knows exactly who created the spelljamming mines, although many people suspect the arcane. It is rumored that the humanoids of Borka have emplaced a number of mines around their space-dock called “the Egg,” leaving a safe channel open for their own ships, of course, as an unpleasant surprise for unwelcome visitors. This has yet to be confirmed or disproved, however. The arcane sometimes sell spelljamming mines for the princely sum of 10,000 gp each. However, not all of them have access to these items, or are willing to sell them. Sometimes mines can be picked up on the “open market” but then there is always a risk-who knows if the arming code is actually what the seller claims it is? 
Category:Encyclopedia Magica Magic Items
Category:Magic Items
Category:Magic Explosive Devices
Category:Magic Weapons