The Apparatus of Kwalish (a fantasy magical item) is a primitive magical submarine.
It appears as a large iron barrel. When a secret button is pressed it opens up, and reveals a very cramped 2 seat cockpit inside. The apparatus is controlled by a series of levers, which (when skillfully used), give it roughly the abilities of a giant crab (pinchers and all).
This device is actually more technological than magical, as only the raising and lowering of the craft, and the headlights are magical in origin. The legs, tail, pinchers, portholes, and such are all mechanical in nature. The craft is very heavily armored (it has to be because it is as slow as molasses), and can withstand repeated attacks from all but the largest sea creatures.
The best use for this device is to scout out underwater areas for later (magical), exploration. It can dive as deep as 900 feet, so it is the perfect craft to take hunting for sunken treasure off the coast of the local islands. There is no real way to exit the craft while it is underwater (not without flooding it), so operators usually have to break their way into sunken ships with its giant claws to look for treasure.
On most worlds only Gnomes will have the proper technological knowledge to repair this device (or build the non-magical parts).
This is only my interpretation of this item, which is based largely upon its use in the older versions of the Dungeons & Dragons series of games. Your Apparatus of Kwalish may vary, so always read the instructions.
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