Kyle McLachlan’s character describes Frank Booth as “a very dangerous man”. That’s putting it mildly. He’s repellent, repugnant. A murderer, rapist, kidnapper. A drug dealer, a drug abuser. Sadomasochistic, volatile, psychotic. He’s an emotional nightmare made flesh, using a lounge singer as his own personal therapy sessions: demanding some form of infant roleplaying one second then physically assaulting and defiling her the next.

God knows what horrors drive a man like Frank Booth. We can only speculate what all the clues add up to. Breathing in some unknown drug; screaming not to be looked at (and like some Biblical warning, Jeffrey does and pays the price); bizarre mother issues; the blue velvet fetish when he embraces a moment of depravity. In a scene that could tip into comedy (but doesn’t — one of Lynch’s brilliant tricks as a filmmaker), Frank stands a foot away from Suave Ben lip-synching Roy Orbison’s “In Dreams”. The song takes Frank to some other place, somewhere he feels safe, loved or nostalgic. Then there’s something that incites him, something that fuels an indignation and he can barely control himself. All within a minute. The man has no filters. It’s all gratification and response.

What’s worse, he infects everyone around him with his darkness (a part of Dorothy revels in the abuse, Jeffry seems to flirt with then embrace his own depravities). Even innocuous pop songs become tainted when he plays them. After witnessing Frank’s visit with Dorothy, Jeffrey dreams about him. Within the surreal imagery, Frank’s appearance is a distortion of rage, an animalistic roar reverberates through him. In the BLUE VELVET universe, Frank isn’t human. Dispatching him means dispatching evil, both in its physical form and the savage seed he plants in those he touches. If only that were the case in the really, real world as well.

Dorothy: “I have a part of you with me. You put your disease in me. It helps me. It makes me strong.”

https://www.youtube.com/watch?v=yP2OwiCmk88#t=45.01105535