Nebulos Triangle

The Nebulos Triangle is an area on the planet Nebulos known for the many disappearances it has caused. It has the distinct ability to make machinery malfunction, though only sporadically, apparently. The area consists out of stone and metal for the most part, with a mercury river flowing down into a metallic sludge-filled lake.

Ladybird Books continuity
With the Decepticons not detectable on any other location on Nebulos, Optimus Prime realized they had not looked for them yet in the Nebulos Triangle and asked his soldiers why. Kup explained about the area's bad reputation among the Nebulans, backed up by information from Quickswitch. So naturally, after hearing this, Optimus Prime didn't hesitate a nano-klik to send a group of three Autobots into the cursed area to check on Decepticon presence.

The Nebulos Triangle's bad influence on machinery first affected Quickmix, then Scoop, who nearly crashed into Quickmix. This made the Autobots decide to continue in robot mode, which didn't go much better but at least safer.

Not much later, a whirlpool in the lake caused Quickswitch to become separated from the others and find himself stuck in an underground cave. Utilizing his drill tank mode, he tried forcing his way out until suddenly he stumbled upon a brightly lit tunnel. He followed it and thus discovered the Decepticons' secret underground base indeed hidden in the Nebulos Triangle.