We found that a flash motion of Ga droplets with Joule heating transformed an amorphous carbon pillar into multiwalled carbon nanotube. Flush discharge into the pillar quickly heated up Ga droplets, which originally incorporated in the pillar due to the fabrication technique with focused-ion-beam-induced chemical vapor deposition, inducing a flash motion of Ga toward negative electrode. Thus, the Ga droplets dug out a tunnel inside the pillar, simultaneously inducing a catalytic transformation into a multiwalled graphitic tube. (c) 2006 American Institute of Physics.