Black coral

Black coral is found in Dolphin Bay in Generation 1

A mysterious black coral growing on the bottom of Dolphin Bay is a source of almost limitless energy.

Fiction

Find Your Fate Junior

DSB The Constructicons discovered the black coral while constructing a hidden base in Mount Lomas. Predicting that it would triple Decepticon warmaking capabilty, the base was converted into a full-scale superfuel refinery.

To prevent unwanted snoopy kids with dogs, the black coral was protected by underwater mines.

From Teletraan I: The Transformers Wiki, a Wikia wiki.