Abra Cadaver - S3-E4
Visible crew/equipment: At the beginning of the episode, when the brothers chat around the central morgue table, the boom mike appears above the table, on the upper side of the screen. (00:04:55)
Continuity mistake: When Red Buckley is about to enter Emil Duval's house at night before discovering the black pearl, the lights inside the house are on, but when he finally enters the house they are off. Later when he goes out, they are on again.
Visible crew/equipment: Crew elbows are manipulating the Crypt Keeper at the end when he pulls the electrocution switch.
Creep Course - S5-E9
Continuity mistake: Professor Finley left behind the tool for removing the brain in his study. Stella somehow has it later in the mummy's tomb.
None but the Lonely Heart - S4-E1
Visible crew/equipment: When the black ribbon lands besides the gravedigger's foot, you can see the crewmember's hand tossing it. (00:08:40)
The Assassin - S6-E8
Plot hole: There's no way Shelley Hack could clean up all that mess of blood and three dead assassins with only an hour or so before her dinner party.
Beauty Rest - S4-E5
Revealing mistake: Kathy Ireland is supposed to be dead but watch carefully and you'll see her chest move when Minnie Driver's doing CPR.