Cassandra Truth: Ned. He tries warning Beverly about Ronan and the lamp, but she doesn't believe his warnings. He had apparently tried warning her grandmother as well, but she refused to listen as well.
Mind Manipulation: Ronan is clearly doing something to Beverly, but it's never really clear what the extent of it is. She goes from resisting his advances to so in love that she upends her entire life for him between edits, and towards the end she shakes it off and is furious.
Our Ghosts Are Different: Ronan is a spectral entity made of "anaphasic energy". He's kinda like an alien incubus, feeding off his victims.
Scotireland: It's supposed to be a planet of Space Scotsmen, but the accents of the people are hardly Scottish. Amusingly, the actor who plays Ned Quint was actually Irish. May be an in-universe version of The Theme Park Version; many of the citizens aren't even human, they just built their colony on the theme.
Voodoo Shark: Ronan's getting on-board the Enterprise by travelling through the power transfer beam was such a silly solution to a non-problem — rather than taking the obvious solution and having him jump into Beverly's body right before she's beamed up — that episode writer Brannon Braga later admitted that for years afterwards he was ridiculed by the show's other writers.