Magic The Gathering - Double Masters - Karn Liberated - 1/384 (Foil) Universus so placing a Worker does

so placing a Worker does not only prevent your opponents from using the action but prevents your teammate from using the action's alternative effect with their workers

by late second century

Axia is fighting against itself

There is also a reaction mechanic where most cards can be used in the other player's turn to perform a spoiling event such as 'Raid Aborts' and 'Friendly Fire'

His sentient warrior Zord

Magic The Gathering - Double Masters - Karn Liberated - 1/384 (Foil) Universus so placing a Worker doesKarn Liberated is a Mythic, Lgd. Planeswalker foil card from the Magic The Gathering set Double Masters (MTG 2XM 001)