A tablet sold as an Ecstasy pill shaped like an Autobot head. May be bright blue, green, or another color, resembling a children's vitamin. Blue Transformers are known to contain no MDMA, instead being made of a cocktail of TFMPP and BZP, chemicals which badly mimic an Ecstasy high while providing the user with a spectacular hangover, nausea, and headache. Especially nasty when combined with alcohol. Spare yourself a bad time and don't buy or eat these. Often found near Portland, OR, and Seattle, WA.
That dude in the back of the club offered me a Blue Transformer, but my buddy was so sick when he ate one last week that I decided to pass.