The Wonder Twins are a pair of twins, Zan and Jayna, teenage alien superheroes who were helpers to the Super Friends in the Hanna-Barbera animated television series of the same name. In the 1990s, these characters were heavily revamped by DC Comics for modern audiences.
The pair made their debut in The All-New Super Friends Hour. Zan and Jayna are siblings from the planet Exxor (also spelled Exor) who were being informally trained by the superheroes. Unlike their predecessors, Wendy Harris and Marvin White, this pair was able to participate in combat with abilities of their own. Their powers were activated when the twins touched each other and spoke the words “Wonder Twin powers, activate!”. (In the comics, it was revealed that this phrase was unnecessary, just a habit of theirs.) As they were about to transform, they would each announce their intended form. For example, Zan would announce, “Form of a glacier!”
Their powers were as followed:
In addition, they had a pet Space Monkey called Gleek who had a useful prehensile tail and whose body could act as a conduit for the twins to activate their powers should they be out of reach. Gleek also served as a courier when the twins needed to travel: Jayna would typically transform into a large eagle, and Zan would transform into (plain) water, “jumping” into a bucket which Gleek conveniently would be holding. (This led to the joke by some fans that Gleek’s superpower was to make a bucket appear and disappear at will. See hammerspace.)
The characters were introduced in the Super Friends comic (where they were far more competent, often being the key to solving major situations) and were ignored once the series was cancelled. Jayna’s powers in the Super Friends comic book were shown to be more extensive, allowing her to transform into even mythical creatures. Similarly, Zan was able to transform into anything tangentially related to water or ice, including a Frost giant.
According to the Super Friends comic book, Zan and Jayna are mutants, evolutionary throwbacks to an ancient race of Exxorian shapeshifters. Their parents died when they were still babies (during a plague), and, because of their origin, no Exxorians wanted to adopt them. They ended up adopted by the owner of a Space Circus, who only wanted to use them as sideshow freaks. Fortunately, the circus’s clown (or “laugh-maker”) was a kind man and raised them. He also gave them Gleek as a pet. Eventually, as teens, the pair escaped the circus and hid on a planet where a space villain called Grax (an enemy of Superman) had set his headquarters. Spying on him, they learned that Grax was planning to destroy the Earth using hidden superbombs. The twins decided to travel to Earth and warn the Justice League; that was how they came to replace Wendy and Marvin (who were planning on retiring as heroes anyway) as their sidekicks. The heroes also arranged for the kids to live with an old scientist called Professor Carter Nichols, and they even took secret identities as John and Joanna Fleming. “Johan” and “Johanna” were supposedly transfer students from Esko, Sweden, disguised with blonde hair (Zan wore a wig, while Jayna used her powers to transform into a human to change her hair color and ear shape), to allow them to attend Gotham City High School.
In the 1990s they were introduced into the main DC Universe in the series Extreme Justice. The series retconned their origin so that they are slaves of an alien villain, later rescued by the Justice League. In Extreme Justice #9 (Oct. 1995), unable to speak English, they accidentally attack some civilians and the Justice League. They join Captain Atom’s team in issue #16. They had far greater powers than their cartoon counterparts. During their fight with the JLA, Zan became an ice golem, a water monster, and a demonic-looking whirlpool; while Jayna became a griffin, a werewolf, and a sea serpent. Although rarely seen today, this version of the Wonder Twins is still part of the current DC Universe. Later they appeared in Young Justice #49–51, wearing uniforms which resembled t-shirts and jeans, to help avenge the murder of Empress’s parents. Apparently, the Wonder Twins enjoy the taste of CDs, as they ate several of Wonder Girl‘s favorite discs.