They were either trying to distract the spider with a snack before making their escape, or offering a sacrifice to their new eight-legged god.
Probably trying to get the cat 'switched on' in a hurry - damn things don't come with a manual, and always seem to have a bad motivator.
Had the same problem with a rodent and two cat units, even locked in the room with the intruder they did nothing more than flick an ear at it. Wasn't until six hours later, incident forgotten, that a sudden rucus signalled the cats had come online and done the deed, took the dog by surprise and he went into full policeman mode barking and chased the cats out of the house like criminals.
Biting the hand that feeds IT
