Interestingly, the figures appear to be screaming horrid screams every few seconds even though they don't respond to external stimuli such as being attacked Elden Ring Runes. In the accompanying text the user stated that they'd been playing for 200 hours before noticing that the bodies that were crucified screamed in the evening.
Close examination reveals that the crucified bodies appear to be dead for a long time. Perhaps they were one of the first casualties during the long war that has ravaged The Lands Between. Death is an uneasy situation in FromSoftware games, and Elden Ring appears to be the same. There are bosses that can be fought well after their deaths.
It's possible that the crucified bodies haven't completely shuffled away from mortal life, or. While the undead bosses aren't in the game the bodies of the crucified seem to be completely immobile and helpless, able to do nothing other to screaming. One Twitter user Lance McDonald notes that the screaming doesn't appear to be coming from the bodies; it only fills the air around them.
As of the time of writing it appears that lots of others Elden Ring fans also didn't understand where the noise was coming from until a while into their game playthroughs buy Elden Ring Items. One user explained that they thought that the sound came through an island that was in the swamp.