The Acid Sea of Junkion is, well, a sea of acid. It's littered with junk and inhabited by Sharkticons who are seemingly immune to its corrosive properties.

Fiction

2005 IDW continuity

Megatron and his guide Pentius were forced to cross the Acid Sea on their journey to the Pillar of Rust, but on arrival at the Corroded Shore they were attacked by local Sharkticons who pulled Megatron into its depths. Rage For some reason they released him before he could succumb to the acid, and he emerged from the sea unharmed to continue his travels. Fallout