Fire-retardant foam

Fire-retardant foam is used to extinguish fires.

In the G1 cartoon episode, The Ultimate Doom Part 1, the Autobots' computer Teletraan-1 releases fire-retardant foam during a Decepticon attack. The foam lands on the Decepticons and begins to short out their cricuitry. Megatron orders an immediate retreat.

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