The Overkilling Machines are a force to be reckoned with in the Dragon Quest video game series. Introduced in Dragon Quest VI as stronger versions of the Killing Machine series and usually the protectors of ruins and treasures. It is unknown who built them or who are they working for; but, as stated in Dragon Quest VII, they are programmed to kill much like their predecessors.
They carry a saber and a mace for battle and are also able to shoot arrows with the crossbow on their "tail", they can even retract the spikes at its base. An advantage is that they don't know many magic spells, but they tend to attack twice.
Dragon Quest VI
Their debut was on this game, alongside its stronger varieties, the Überkilling Machine. They appear at Pegasus Pillar as some of the strongest enemies in that dungeon, this monster is able to attack twice per turn.
Dragon Quest Monsters Joker 2
An Overkilling Machine appears as the mid-boss of Bemusoleum and is avaliable to recruit if a Dragon Quest VI game is linked.
Its japanese name, Killer Machine 2, suggest it may be an upgraded version of the Killing Machines, another populr and recurring monsters.