What about a "living" bed that is in a symbiotic relationship with its bugs?
Say the bugs are something mutant, and through their bites, inject a strong neurological toxin that completely knocks out the victim sleeping in the bed, granting them an unusually heavy sleep, as well as incredibly vivid dreams. During this sleep state, the bed - not the bugs - begins consuming the victim. Through some means I can't even begin to imagine, a sleeping person completely disappears into the metaphysical maw of the bed in a span of 8 hours. The bed leaves some sort of runoff, a thin residue of sorts; the bugs consume this and are nurtured by it. I imagine this bed would be in some hotel, eating poor bastards left and right until maybe someone was caught mid state - by someone walking in perhaps, and thus the SCP Foundation got a hold of it from there.
Could go on. Eh?