When Halley's Comet passed by the Earth in 1986, I remember that they came out with a toy line to cash in on it. They were these ordinary looking vehicles, like cars, trucks, etc, that could transform into giant robots and monsters. The idea was that it was the comet's passing by the Earth that would cause them to transform.

Anyone know what I'm talking about?

I don't recall these toys, I'll have to keep an extra eye out for them. I remember when Haley's Comet passed though. :D

This seems like it was a Transformers type toy that came around the time the Transformers was popular.