Awesome Historic Creature: The Repeater

Also called the Ditto.  I am not kidding.

This creature's most feared ability is its snort. The monster can snort at the end of any melee round, and no other limit applies to the frequency. Its snort produces an odd feeling of entrapment in all life forms within 300 feet of the repeater. Each victim within range must make a saving throw vs. Magic Spell. If successful, the victim resists the trap; but if failed, the victim falls prey to the infamous repeater effect.

Any victim of the repeater effect must repeat all of the previous round's actions. The repeater, of course, is under no such compulsion, and acts with deadly foreknowledge of its victim's actions.

    - Frank Mentzer, Dungeon Master's Guide to Immortals, 1986

I'm fairly certain that by the time Immortals came out, ideas were running short.  Still, I gotta love the blatant use of "things around the office" as creatures.  First the bag of dice, then the copy machine.