shrooms/LSD are the true hallucinogens, and they are very similar. everything is brighter, textures and patterns are visually amazing and tend to move. Definitely do these somewhere you can experience nature. I've examined a cactus for a couple hours, before. You'll get lost in you own head, time will slow down, there's a potential for euphoria, a potential for anxiety.

MDMA is part stimulant, part hallucinogen. I am tempted to recommend it because its almost impossible to have a bad first time experience, but its riskier. addiction potential, overdose potential. It's all euphoria, plus colors are brighter, music is amazing. You must do it with other people, it makes you feel more connected to them, and that's the best part. drink LOTS OF WATER

Whatever you do, start with small, small doses. and make sure someone is with you who is either sober, or really knows what they're doing. Do not drive. and be aware that legal penalties for possessing these substances are pretty sever in some jurisdictions and could significantly fuck up your life if you get caught