KILLBOTS

The Killbots from Futurama have two attributes I'd love to utilize:

Kill limit

For unknown reasons, a kill limit of 999,999 is hardcoded into killbots. I'm thinking of a large, old-style LED counter, red -of course -displayed prominently on the chest or torso, which increases as it kills, accompanied by a pleasant "BING!"  Perhaps lesser models have a limit of 999, or 99.  When the kill-limit is reached, they become peaceful and in fact rather friendly. Perhaps the players encounter one that is within one or two kills of its limit... however, their kill counter has the option of being reset, possibly unintentionally...

Activation

Killbots start shooting immediately when hearing a word that has to do with weapons. Supposedly, this has been installed to easily activate the Killbots on immediate demand, but it also causes troubles, including accidentally shooting each other or themselves when talking to each other.
Imagine a sealed vault containing a massive Warbot of the Ancients, possibly the very first chamber of an underground complex, or central nexus to lvl one, which the party will surely have to pass through numerous times.  It remains completely unresponsive until one of the PCs happens to mention "that wound I took in the arm", or "wish I still had that Fireball", or "I only have 3 charges left in my Wand of Magic Missiles"... whereupon it immediately "lights up" and a powerful vibration/hum is felt/heard as the automaton intones "Arm/Fire/Missiles!" and launches the appropriate attack!  Maybe its sealed behind a partitioning wall of Glassteel or some such, and just maybe that accounts for the obviously dead and contorted - but not obviously wounded (?) -corpses in there as well, victims of the colorless, deadly poisonous gas which has kept the Killbot insulated from the effects of time for so long... maybe the party should be given a rnd to prepare, as the machinery supporting the Killbot evacuates the poison gas before lowering the barrier... this might actually give them a chance against the thing... and of course, if the Kbot is defeated, the machinery will raise the barrier again in 10 rnds, and refill the chamber with gas... better loot those corpses quickly!