When I was in college my friend had a party. My girlfriend and I decided to have some drinks alone before heading over to the party. We probably showed up a couple hours after the party had started.

The minute we walked in the door something felt off. No one was interacting. Everyone seemed to be in their own little space. Some people were just sitting and staring across the room at each other. One guy was talking to a poster in a serious manner. Another guy was wrapped up in the curtains leading to the porch. There was a girl sitting alone in the kitchen mumbling something to herself about death. My girlfriend and I were both pretty drunk, so it was hard to process what was going on. No one could talk straight with us. The whole place was just really strange. We lasted all of 30 minutes before deciding to leave.

The next day I asked my friend about the party and it turns out it was a "mushroom party" where he gave everyone mushrooms when they showed up. Being late, we missed the onset period and happened to show up when everyone was already tripping.

TL;DR - showed up to a "mushroom party" drunk and confused. Strange shit was seen.