No SWIMing here, it doesn't protect you and it just looks stupid. Hop on out of the pool
Yellow marquis almost always means some kind of cathinone, that means it could be MDPV, methylone, butylone, mephedrone or like 100 other chemicals. Sorry man, we can't really say for sure.
What I CAN tell you for sure, is that that is NOT MDMA and belongs in the trash! You buy a reagent so you don't have to take adulterated chemicals.... so use it!!