In Caged Heat, “[t]he ghouls were originally going to be a big-ass, Lovecraftian tentacle…In the first draft, Dean gets thrown into this underground pit where there’s just sand and a huge trough of water. He starts digging and finds a bone, and realizes he’s been thrown into a monster pen. Then this huge tentacle reached up and grabs him and sucks him under. Sam busts out with a fire axe and chops the tentacle off and pulls him out, but Dean’s leg’s all messed up. It was going to be this very bold step into the realm of monster, but it was just too expensive. In the [mid-season shooting] break, Bob Singer was less convinced than the rest of us, but Eric was like, ‘No, no, we can do it.’ So we thought, ‘Great!’ but so many other things on the episode were so ambitious that it became the thing that went away.”
“Ghouls are good, but I think we will always miss the tentacle.”
— Brett Matthews in Supernatural: The Official Companion Season 6. Titan Books, 2011: 59-60.