MDMA, short for Methylenedioxymethamphetamine, is a psychoactive substance first invented in 1912. Unlike all of the above substances, MDMA is not a traditional psychedelic. It does not cause any typical psychedelic effects. Instead, it is an enactogen, which are substances that produce experiences of emotional communion, oneness, relatedness, and emotional openness.  

It is also commonly referred to as Ecstasy, though this is when pure MDMA is pressed with another type of substance, often an upper.