Liquefaction is the ability to liquefy through metal and other solid objects. It is mainly used by Machine Mutants to move through the walls and ground of planet M-2. Super Buu and the frog monster Susha also use the technique.
Super Buu uses the technique as part of his Dangerous Liquid Bomb attack. The Sigma Force and General Rilldo use it in their battles against Goku, Pan, and Trunks. Natt uses this ability greatly when messing around with Pan, liquefying through another part of a wall when she was about to attack. The other Sigma Force members use the ability during their battle against Goku.