Mafūba (魔封波, Demon Sealing Wave, Magic Seal Attack, Demon Incarcerator, Evil Containment Wave, Mafūba Wave) - a technique designed to seal demons away by sucking them into a container with a special "Demon Seal" ofuda on it. The move requires so much of the user's life force to perform that those who use it, whether successfully or not, are likely to die soon afterward. This move was first used against King Piccolo by Mutaito to trap him inside an Electric Rice Cooker (called the Denshi Jar by fans) during his first rampage. The "Denshi Jar" can be any type of container, as long as it can be sealed shut after the technique has been completed. However, the smaller the container, the harder it is to aim the target into its opening.
After Piccolo was released from his prison (Denshi Jar) by Emperor Pilaf, he was confronted by Master Roshi who nearly succeeded in using the Mafūba to contain him again, but missed at the last second and then died shortly afterwards. The attempt was witnessed by Tien, who learned the Mafūba from watching Roshi perform it and practicing a scaled-down version of it himself several times. When he finally confronted Piccolo, he was not able to use the technique successfully as Piccolo's son, Drum realized what Tien was attempting and sacraficed himself by jumping in front of the blast and was ensnared and about to be confined to the wlectronic jar. Piccolo quickly destroyed it before the attack was successful, saving Tenshinhan, releasing Drum from the jar and therefore rendering the containment wave useless (in the manga, the container is damaged from Tenshinhan's practice attempts and therefore he does not even attempt the move).
In the later confrontation between Kami and Piccolo Jr., Kami demonstrated his knowledge of the technique and attempted to use it to seal away Piccolo. Piccolo countered with his Mafūba Gaeshi (Reverse Mafūba) technique which he was able to use against Kami and seal him with. Neither Piccolo nor Kami died as a result of the Mafūba usage, and Kami specifically stated that it would be a way for him to get rid of Piccolo without dying himself (their lives were connected so that if one died, the other would as well). It can thus be surmised that if one is sufficiently powerful, they can use this ability without perishing (however, both Kami and Piccolo are Namekian, meaning their ability to regenerate may have prevented them from dying. A Namekian's enhanced lifetime may also be the cause of Kami not dieing; i.e. his life would've been shortened by draining a significant amount of life energy, but due to his ability to live for hundreds, he survived). Kami's knowledge of the technique might mean he taught it to Mutaito, however it is unlikely as Kami would have probably faced King Piccolo (as he is Kami of Earth and Daimao was his responsibility) had he known Mafūba at the time, rather than have taught Mutaito a technique that would cost him his life just to seal the evil Daimao, while Kami himself could do it and survive (However it is possible that Kami used the Lookout's Pendulum Room and learn the Mafūba straight from Mutaito himself).
Piccolo knows how to both reflect and then use this technique properly. If he didn't know how to initiate it earlier, then he certainly gained that knowledge after merging with Kami.
Garlic Jr. used this attack on Kami in order to take over the lookout and to release the black water mist on the Earth. He had earlier used the Dragon balls to gain immortality, so he obviously didn't die by performing the attack.
In video games
In the video game Dragon Ball Z: Super Sonic Warriors, Piccolo uses this against Super Buu at the conclusion his story mode when he found that even after merging with King Piccolo (which increased his power to one equal to Super Buu) he could not destroy him, yet he does not die performing the technique. (Note: Kami didn't die when he originally performed the technique. At this point in the Piccolo is fused with Kami and a Super Namek, thus would be more powerful enough to perform it without dying.) Piccolo successfully uses it to seal Buu in a bottle and places it within the Hyperbolic Time Chamber as a precaution against Buu's release, with Piccolo remaining guard within the Lookout; later in Piccolo's bonus scene, Buu is accidentally released by a dimensionally-displaced Gotenks (a Gotenks from the original, "non-what if" timeline), but is finally defeated by Piccolo (with help from a confused Gotenks).
- Mutaito - (Ancestral skill; used it to seal King Piccolo in the Denshi Jar, sacrificing his life & saving the world; Piccolo later released by Emperor Pilaf & defeated by Goku)
- Master Roshi - (Learned it after witnessing its use by Mutaito; died attempting, later revived via the Dragon Balls)
- Tien - (Learned it from watching Master Roshi's attempt; never successful completes the move in battle)
- Kami - (Could use it without dying; because Piccolo Jr. is his evil half, was countered by Majunior's Mafūba Gaeshi; was seal in a bottle by the move twice in the series)
- Piccolo Jr. - (created the Mafūba Gaeshi to counter it)
- Garlic Jr. - (immortality likely prevented death; used to seal Kami in a bottle)
- Master Shen - (Witnessed it successful use by Mutaito and would be possibly be able to perform it; however would probably be unwilling to sacrifice his own life to use it, nor was he ever in a position that necessitate its use)
- 魔 (Ma) = Demon
- 封 (Fū) = Seal / enclose
- 波 (Ha/Ba) = Wave