People confuse psychedelic with experimental, but psychedelic formed years after Pink Floyd broke up.
In the 21st century The Mars Volta came, with a skilled guitarist and a singer with a strange voice that fit their strange style. they had dedicated an album titled "De-loused In The Comatorium (an auditorium is a place for listening so a comatorium would be a place for being in a coma)" to their friend who went into a coma, came out of it then commited suicide. The album is from the point of view of a fictional character. He goes through battles in his mind while he is in his coma and he wakes up and then kills himself.
Example from song "Roulette Dares(The Haunt Of)":
Specter will lurk
Radar has gathered
Midnight nooses from boxcar cadavers
The Mars Volta's experimental sound is like Pink Floyd's except they are hundreds of times more experimental than Pink Floyd and their kind of sound is different. Instead of being lifted into a dream you are being thrown into another world and pulled extremely fast by and invisible force. But in other songs like Televators, its like standing in the middle of someone elses dream and everything in that dream you have never seen before,...