Does anyone know in which episode of the original cartoon did they find this big 尻, お尻 lake of bulletproof liquid gold-like metal?

Apparently, this stuff was like blaster-proof paint; the Decepticons ended up skinny dipping themselves in it and proceeded to kick Omega Supreme's butt.

Later on in the episode, Omega Supreme and the autobots all get dipped in the stuff and the ensuing battle destroyed the lake.

I don't know a whole lot about the 表示する (I hope I spelled Decepticons correctly!), but I remember this cool episode vividly from my childhood and it seemed to have some environmental message, as well.