Anafrog

The Agnew Analog Reference Instrument Type 8001 is a unique electrochemical synthesizer, generating strange sounds through chemical reactions occurring in the built in reactor cell.

Something of an oddity, which I first experimented with 12 years ago or so, but now finally built as a "portable synth to fit in a backpack to tour with", for a friend into noise.
I shall call it a vacuum tube electrochemical synthesizer.
It is a miniature galvanic cell, passing current through an electrolyte, causing an electrochemical reaction. This is translated into electrical signals by the vacuum tube electronics, which also offer an inductor filter and feedback loops.