And Santa may not be alone. Howard tried to gently push with his car Sheldon in an office chair out of his new parking space. (Makes Sense In Context) Sheldon accuses Howard of trying to run him over. Howards' response was essentially "Hey don't get mad 'cause I was living the dream,". Howard dreams of running Sheldon over!
Howard: I'm an advocate of mitosis. One day he'll eat an enormous amount of Thai food and split into two Sheldons. Leonard: On the other hand, I believe he's the larvae form of his species and one day he'll split the cocoon and emerge with moth wings and an exoskeleton. Penny: Okay, well, thanks for the nightmares.
In Season 5's "The Infestation Hypothesis", it's never shown what exactly was crawling around inside the chair Penny picked up off the street. Its size, shape, and movements seem to indicate a mouse or a small rat, which would be scary enough, but the fact is we never find out for sure.
Earlier in that episode, Sheldon has a horrifyingNightmare Sequence involving a swarm of roaches crawling out of the chair and burying him alive.
Early in the first season, Penny lets slip to Sheldon that Leonard may have made light of Sheldon's accomplishments. The sight of a genuinely pissed-off Sheldon, towering over Penny as she backs away, demanding to know what exactly Leonard said. Up to that point, Sheldon had largely been played as a Cloud Cuckoo Lander, but seeing that scene, you could very easily believe it when Leonard says that Sheldon is one lab accident away from becoming a super-villain.
Stuart's entire life. His misfortunes may seem funny to us who watch him, but try to put yourself in his shoes. His life is basically an endless series of nightmares that come true.
Until he met Howards' mother, and with her help, get back onto his feet. In fact he has become a regular of the BBT gang. Whatever hell he has experienced, he doesn't have to face it alone now... until everyone move on with their lives and he's alone again, as seen in one episode where 20 years later he is standing outside the apartment building waiting for everyone else to show up for a meeting they all had set.
The two HUGE rats that attack Raj in "The Expedition Approximation."
In "The Hot Troll Deviation", Howard, using a recording of Sheldon saying "Penny", tricks Penny into opening the door by imitating Sheldon's signature knock. Penny then states she wouldn't have opened the door if she knew it was him after he gave her a teddy bear that turned out to contain a webcam.
Leonard's red and raw body when he removes the sweater in "The Itchy Brain Simulation". And then to find out that Sheldon deliberately manipulated Leonard into wearing it for days. "One lab accident away" indeed...
Bernadette threatening an airport employee to have her mother in law's ashes found and returned to them with murder (albeit used for comedy), one only has to wonder why she didn't call security on Bernie. But imagine trying to do your job and it's really stressful and demanding and then comes the situation of lost luggage and having to locate it. Now, you can always expect your customers to be upset and extremely angry with you but one of them threatening to kill you if you don't do your job?
Raj and Howard are watching horror films in order to prep Raj for his date with Emily. The two are completely freaked out by the movies she picked out. Howard verbally sums up what they've seen so far, and it's stuff far more horrific than you're ever likely to see in any mainstream horror film. Raj isn't sure he wants to date someone who watches that kind of film, and he questions Emily about it. Her response? "They kind of turn me on." Raj is too horny to consider the implications and just presses play, but just think of what that means, what kind of terrifying things must go on in Emily's brain...
Far more horrific? Goodness, no. The movie they discuss watching is 100% real. Sweet dreams.
In one episode, Leonard comments that nobody goes into science for the money, at which point Bernadette dismisses him with a "Speak for yourself, my research team just invented and cured restless eye syndrome. Kaching ya blinky chumps!" The idea of scientists inventing new diseases just to make money off the cure is deeply unsettling in how sociopathic it is.
Less so if it was actually classifying a already common body quirk as a syndrome. B.O, Halitosis, foot fungus, all of these existed since the beginning of time, and only recently were these classified as disorders. And thus the personal hygiene companies rejoiced, and so did people with the miracle cures that helped with such diseases. Bernadette could be saying that her company classified something as a disease and they have a cure for it. Hooray for marketing! The real horror is the psychosomatic symptoms people are bound to have induced by the very idea of R.E.S, and that the only cure is to buy and use the product. The idea is a mind virus itself, manipulating people to seek a cure for a previously unnoticeable disease! Bernadette just spread the mind virus to The BBT gang, and now YOU!
Stuart watching Howard and Bernadette while they sleep is just plain chilling.