Rust Spot

The Rust Spot is one of the worst regions of Cybertron, several hundred miles wide and with every inch of it packed with hazards: nuclear winds, Toxic Sludge Swamps, Slicers, mist that corrodes your body while also disrupting your navigation systems... you name it, the Rust Spot's got it. Any reasonable Cybertronian would avoid the place, but for those in the know it's got a network of underground tunnels safely hidden away from all the dangers.

Fiction

IDW Generation 1 comics

As Bludgeon's Decepticons held Ratchet captive in the tunnels beneath the Rust Spot, Orion Pax and Nightbeat were sent in to perform a hostage exchange, guided by Alpha Trion, foremost expert on the unmappable region. They were attacked by Slicers near the Tesk Crater, but chased them off and were taken to the Decepticons' underground base, where Bludgeon revealed that the reason he'd picked the Rust Spot as the stage of the exchange was so that he could trap and capture Alpha Trion. Omega's Conundrum