4-MMC and GHB
4-MMC is sometimes combined with GHB to take the edge off the 4-MMC or to make you hornier when used in a sexual setting. The risk of the combination is that you will not feel the anesthetic effect of GHB due to the stimulating effect of 4-MMC, which increases the chance of overdosing with GHB. If you then take too much GHB, your body is still stimulated, but you are no longer or not fully conscious. That can look very weird. Someone then moves very strangely but it is not possible to make (proper) contact.
Here you can read more about what to do when somebody passes out.