Most attacks in the Dragon Ball franchise come down to the sheer power afforded to them. But there's one technique, introduced in Dragon Ball before becoming more prominent in Dragon Ball Super, that can counter even the most powerful of beings. However, it does come with a major power cost -- one that many heroes have had to pay in the past.
What is the Evil Containment Wave, how does it work -- and why does it so often risk the life of the user?
The Evil Containment Wave -- otherwise known as the Mafuba Technique -- is a special ability within the Dragon Ball universe. Invented by Master Mutaito -- the same man who served as a teacher to a young Master Roshi -- the Evil Containment Wave creates a massive green storm of energy around the target. If the attack successfully strikes the target, they are reduced to an energy form, reduced in their power and sealed away within any container. This technique can counteract incredibly powerful or even immortal enemies, trapping them away and leaving them unable to utilize their overwhelming power against their enemies. All that's required is knowledge of the move, an object to trap them in and a specific paper amulet to seal the object.
Even if the target eventually escapes their confinement, it's clear the attack takes a psychological toll on the victim, as both King Piccolo and Fused Zamasu -- two terrifying and ruthless villains -- were both left shocked and horrified by the technique after escaping. However, there are two major drawbacks to the technique for the user, too: the first is that the move can be dodged or countered by a clever enough opponent, with the user even being potentially trapped inside. The other after-effect of the ability is far more fatal. Using the Evil Containment Wave drains a ridiculous amount of energy from the user. If someone isn't strong enough, then using the technique can drain them of so much energy that it kills them.
This was the ultimate fate of Master Mutaito: while fighting alongside Roshi, Shen and his other pupils against King Piccolo decades before the events of Dragon Ball, most of them died in the conflict. With no other choice, a wounded Mutaito used the Evil Containment Wave against King Piccolo, successfully sealing him away in a rice cooker. The effort cost Mutaito his life, leaving his two remaining students to mourn him. The technique has been used sparingly since then, usually reserved as a last resort by Roshi and his pupils. However, it remained a powerful weapon against very powerful threats. Roshi attempted to use it on King Piccolo when he was released from his original prison, but the attack missed and cost Roshi his life.
The attack wasn't used in Dragon Ball Z but instead began making reappearances in Dragon Ball Super during the battle against the immortal Future Zamasu. With little other way to defeat the villain, Goku (in the manga) and Future Trunks (in the anime) learned the technique themselves to counter Future Zamasu. Although the technique is effective in both mediums, the failure to bring a paper amulet to complete the ritual leads to Future Zamasu breaking free, forcing a more dramatic end to the saga.
Notably, neither Goku or Trunks are killed using the technique -- suggesting they'd become powerful enough by that point to negate that weakness. The draining elements of the technique are still present for Roshi, however, as he uses the move multiple times across the Tournament of Power arc. The use of the technique quickly drains Roshi of most of his power, leaving him injured enough for Vegeta to suggest retiring from the conflict so he can eat a Senzu Bean on the sidelines and avoid unnecessary death.
