Batman Grabs a Gun: Luke is offered and accepts a job as a part of a bank robbery while under the influence of a mind-altering drug. He is given a big revolver and goes to the back to practice shooting bottles. Luke is on permanent "probation" for running moonshine and a part of his probation is a ban on using firearms, though he knows how to use them of course. He later uses the gun to threaten Boss Hogg during the bank holdup.
Easy Amnesia: When the tainted water wears off Luke has no idea what he has been doing for the last 24 hours.
Eat the Evidence: Rosco puts a videotape with the proof that Luke participated in the bank robbery in the back seat of his patrol car with his dog Flash. Flash chews up the tape rendering it useless.
Heroic Dog: Flash plays the unwitting one when he begins eating the security videotape Rosco was delivering to the FBI. That, plus Boss knowing a little too much about the robbery of Hazzard Bank, forces Rosco to drop any pending charges against Luke (although they do stick against the other two robbers).
Hilarity Ensues: In the real world, Luke wouldn't have escaped felony bank robbery charges ... even if Boss knew that a robbery was going to take place. (For that matter, Boss would have been in legal trouble, too.) The lack of a security tape and Luke's drugged personality are the given reasons why he never gets charged.
Jerkass: Which is what the usually even-tempered Luke becomes after drinking the tainted water.
Just in Time: Subverted. Bo and Enos race to the bank in Enos's patrol car knowing that Luke is going to rob it, but get there just after the robbery has happened. Now they have to chase Luke who is driving the General Lee.
Out-of-Character Alert: When Luke starts acting like a Jerkass everyone notices, though for a while they don't know the reason or the cure. Doc Appleby suggests he might have been bitten by a spider or snake, but won't know for sure unless the Dukes get Luke to him for an exam.
Right on the Tick: The tainted water stops affecting Luke exactly 24 hours after he drinks it.
The Smart One Turns Traitor: Luke, temporarily. He is willing to help two known criminals rob a bank, without regard that Uncle Jesse would likely have to hire an expensive attorney to defend him (and it would likely mean foreclosure of the farm).
Spaghetti Kiss: Crossing over with Accidental Kiss, Rosco kisses Boss Hogg when Rosco tries to eat some of Boss's saurkraut which Boss is raising up to his mouth.
Technobabble: How and why the brain-altering drug works. For 12 to 24 hours the subject experiences a severe altering of their personality.
This Is Your Brain on Evil: The main plot driver: Luke drinking water tainted with a serum that alters one's personality, from good to bad.
Water Source Tampering: An accidental version. One vial of a brain-altering drug falls out of the van transporting it back to the lab and lands in the local creek. Luke happens to take a mouthful of that water while filling a water jug to put in the General Lee's radiator.
You Have to Believe Me!: Jesse and Daisy fail to convince Rosco that Luke's participation in the bank robbery is due to a mind-altering drug.
