Cheese contains tyramine (an amphetamine derivative) and certain other centrally acting sympathomimetics as well as high levels of certain amino acids (NB.. L-tryptophan) which are melatonin (your sleep hormone) precursors

It is quiet feasable that cheese late at night would cause a peak in melatonin production in the pineal gland 4 hours after ingestion...

To a person unaware of the phenomena of lucid dreaming, a LD may appear or be conveyed to others as a 'nightmare' ie. dreaming while aware of the dream might be nightmarish to certain uninformed people...

I recommend a good extra mature cheddar - contains the highest levels of active ingredients if ya fancy experimenting... dont scoff too much though, or your stomach will regret it in the morning...