Potara (Zekons)

The Potara (ポタラ) are earrings worn by the Supreme Kais and their attendants for generations. Despite being worn so casually, they are actually an incredible power-up item.

Overview
These earrings are worn by all Supreme Kais as part of their standard outfits, and come in various colors. When one pair of Potara earrings are worn by a single person they have no special properties. However, if two individuals each wear one earring on opposite ears, the true power of the artifacts is revealed. The earrings have the ability to fuse two people into a single entity, substantially enhancing the abilities of both individuals. The resulting fusion lasts forever for Kais (lasting even after death), even if the fused being removes the earrings, so caution is needed when handling them. However, there is one instance where the Potara Fusion will be nullified and restore the fused being back to their original forms in rejection, which is when the fusees are not Supreme Kais. In this case, the fusion only lasts an hour. If a fused being removes their earrings, they can then pass them on to another pair of individuals to use, as seen with Old Kai giving Goku his earrings (who eventually uses them to fuse with Vegeta and form Vegito).

In addition, both users should not be transformed while fusing, as the fused being will not be able to power down from the transformation. As a result, certain transformations, such as Super Saiyan, can put a significant strain on the user's body and shorten his or her lifespan.

Old Kai gives his pair to Goku as a trump card for defeating Super Buu. In addition, the Eastern Supreme Kai and his attendant Kibito merge without knowing a thing about Potara fusion.

If two non-equal beings combined, the superior one will be in control, as seen with the Old Kai. In the case of two equal beings, the fusion will form an entirely new being with a personality traits of both fusees. This can be indicated when their voice sounds like a combination of two beings as seen with Vegito. The being also retains the memories of the individuals. In either case, when the fusion occurs, both fusees cease to exist. This is evidenced when Goku can't afford to use Dende as a partner because his existence is linked to the Dragon Balls.

The fusion can be used on both a deceased being and a living being, in which case, the resulting being will be living.

While the fusion is normally permanent, there are at least two methods shown to be capable of undoing it. The first is if there isn't a Supreme Kai as a fusee. If this happens, the fusion will last only an hour. Also, in Vegito's case, his power was so immense, it forced the fusion to end much earlier. The second known method is to simply wish for the fusion to be undone through the Dragon Balls.

In Dragon Ball Super, Goku Black seems to be wearing a green Potara earring in order to use the Time Ring in his position. The Potara Fusion was mentioned again by Gowasu and Zamasu, as Gowasu appointed him briefly to the rank of Supreme Kai by wearing a Potara correctly, so he can use the Time Ring. Gowasu suggested that they could fuse permanently if they wish so, but Zamasu rejected the offer for later. It is also revealed that if you wear one of two Potara rings on the same ear, the two beings will not fuse.

Gowasu revealed that the reason why Goku and Vegeta did not stay fused the previous time was because they were not Supreme Kais and that non-Supreme Kais would only stay fused for an hour. At least one Fusee would have to be a Supreme Kai in order for the fusion to stay permanent. However, if the fusion uses up too much power, the fusion could not be sustained for the full hour as in the case of Super Saiyan Blue Vegito, who defused mere moments before dealing the finishing blow to Fusion Zamasu.
 * However, in PR/Sentai series, it was still can be permanently even though Gowasu saying.

Potara Fusion
Potara Fusion (ポタラの合体) is similar to the Fusion Dance technique, however unlike the Fusion Dance, the Potara Fusion lasts an hour (permanent for Supreme Kais). The first example is when Vegito is separated into Goku and Vegeta, the two individuals who had fused to form Vegito, soon after being absorbed by Super Buu. Also, while with the Fusion Dance the post-merged clothing is the native dress of the people of Planet Metamor, when merging with the Potara not only are the two people's bodies mixed together, but their clothing is as well. The resulting fusion will have the power of both fusees multiplied by each other. According to Old Kai, usage of these earrings to fuse is vastly more powerful than the Fusion Dance, thus creating an entity that is much more powerful in comparison.

There are five known Potara Fusions seen in the series:
 * 1) Chronologically, the first was a fusion between Old Kai and an old witch.
 * 2) The second was the fusion of Supreme Kai with Kibito, (which they voluntarily performed to test their Potara earrings, not realizing the fusion would be permanent).
 * 3) The third Potara Fusion was the most prominent. Goku fused with Vegeta to form Vegito for their first time. However, the fusion was cancelled after Vegito was absorbed by Buu.
 * 4) The fourth fusion occurs when Future Zamasu and Goku Black fuse to form Fusion Zamasu.
 * 5) The fifth fusion is the second fusion of Goku and Vegeta to form Vegito. The fusion ended earlier than an hour due to the overwhelming energy consumption of the Super Saiyan Blue form.

To use the Potara fusion, the two fusees each take one of the two earrings and put them on opposing ears. The two will automatically merge as soon as the earrings are put on. Those wishing to fuse do not necessarily have to be wearing earrings from the same set in order to do so. Kibito and Supreme Kai simply remove their left and right earrings respectively and before they can react, they are drawn towards each other and subsequently fused together. Despite this, Kibito's earring (which was blue in the anime) becomes the color of the Supreme Kai's earring (which was yellow).

Another oddity of Potara fusion is that unlike the Fusion Dance, the more dominant spirit of the two fused individuals takes precedence over the weaker not just in looks but in voice as well. The proof of this is that both Old Kai and Supreme Kai seem to be the ones in control of their fused forms while having a few noticeable traits from the Old Witch and Kibito respectively.

The Potara Fusion does have devastating weaknesses when used improperly. Should the two fusees have different body types of immortal and mortal, such how as Future Zamasu and Goku Black became Fusion Zamasu, the body will slowly start to deteriorate. Not only physically, but mentally as well. Fusion Zamasu's right side had become purple, and his arm began to melt and expand, despite using a healing technique. This conflict also was shown to turn the ordinarily calm Zamasu insane, wildly attacking.

Other abilities
A sharing of the Potara of a Supreme Kai rank enables anyone to use the Time Rings to travel into the future and return to the present.

Trivia

 * Several characters in the franchise wear earrings similar in style to the Potara, among them are: Zarbon, a man bearing the same symbols as Nok in the audience of the 28th World Martial Arts Tournament, Don Kee, and the Demons Towa from Dragon Ball Online and Dragon Ball Xenoverse and Demigra from Xenoverse and Dragon Ball Heroes.