Steel Beam Bot

thingiverse

The autonomous sentinel disguises itself as a steel beam at key locations, biding its time until activation is triggered. Upon activation, the bot swiftly expands its mass and executes its mission with precision. Typically, these sentinels are equipped with a heavy-duty laser cannon as their primary destructive force. They can be found in high-tech facilities comprised of numerous nano tech bots, all waiting for the signal to spring into action.