Crisis Arm is Robo's 13th Mechanical Arm in Chrono Trigger. It has an attack score of only one and can be found in Geno Dome after defeating Mother Brain. It only sells for 1G.
Mechanics
Damage is determined by multiplying 0.5 by Robo's last Hit Point. The critical hit rate is 5%.
Etymology
Crisis, in the title, implies an urgent situation with an outcome better or worse than the crisis itself. The relatively low damage done by this weapon seems to allude to that.