One day while working in his laboratory Hank Pym accidentally dropped and smashed some vials containing various unknown gases. The gases caused Pym to develop a severe case of schizophrenia. He took the new identity of Yellowjacket and made himself a new suit. After he claimed that he had murdered Pym, he kidnapped Janet van Dyne, and proposed to her, as Pym had long wanted to do. Realizing that Yellowjacket was really Pym, van Dyne decided to play along, fearing that she would worsen his psychological condition if she did otherwise.
The Avengers, not suspecting at first, were shocked to hear that she said yes to the proposal. Van Dyne and Pym, as Yellowjacket were married at the Avengers Mansion amid an assembled who's-who of superheroes active at the time, as well as some villains who were hiding and secretly pretending to be the caterers. Immediately after the marriage, the Avengers were attacked by the Ringmaster and his Circus of Crime. The shock of seeing van Dyne in danger of death (via the Princess' python), shocked Pym back into his normal personality. The Avengers defeated the Ringmaster and company. Despite the fact that Pym was married under an assumed name, the marriage between Pym and van Dyne was still legal, and Pym and van Dyne happily agreed to let it stand. 
Pym eventually renounced his power and used the name and costume of Yellowjacket in crime fighting. Pym spent periods of time with the Avengers, the Defenders, and also briefly returned to his Ant-Man persona for a short time (becoming trapped at ant size for a while), but he spent most of his time completely devoted to his scientific research. He gave his blessing to Scott Lang when Lang used his old equipment to become the second Ant-Man. 
Rita DeMara stole the original Yellowjacket Suit from the Avengers Mansion, and modified it for her own use. DeMara, as Yellowjacket, clashed with Janet van Dyne, the Wasp, when DeMara raided Hank Pym's former laboratory in van Dyne's New Jersey home. The Wasp easily captured the new Yellowjacket when DeMara became hysterical upon using her helmet's cybernetic size-control devices to shrink herself to a tiny size. At that time, DeMara could not adjust psychologically to being so small, although she later learned to do so.
In the search for a way to save his son Augustine Cross, Darren Cross became aware of a microscopic lab available inside Ant-Man's Helmet. Cross kidnapped Egghead and took him to the S.H.I.E.L.D. evidence locker where the helmet was being kept after Lang was arrested, so he could access the laboratory and use it to save Augustine. While exploring the lab, Cross came across a prototype battle armor built by Hank Pym which used its wearer's Pym Particles as a power source to turn the suit into a quantum weapon. Captivated by the prospect of power, Cross donned the armor for himself.
Size Alteration: The Yellowjacket Suit allows the user to shrink to the size of an ant, approximately one-half inch in height, or grow to gigantic height by means of the subatomic particles known as the Pym Particles. The Particles would be released by the suit by way of a special gas.
Bio-Energy Projection: Also known as a Bio-Sting the gloves of the suit can fire powerful bursts of bio-energy.
Flight: The suit has artificial wings which enable the user to fly while reduced in size.
Insect Communication: Like Ant-Man's Helmet, the cowl of the Yellowjacket Suit allows the user to communicate with insects.
|On Earth-199999, Darren Cross used the Yellowjacket Suit based on Ant-Man's Suit designed by Dr. Hank Pym. Via exposure to Pym Particles the suit allowed the user the ability reduce the space between his atoms reducing his size and increasing his density. The suit could generate powerful bio-electric blasts. The exact power source and upper limits of this ability are unknown. It was equipped with some type of rocket or jet propulsion system. However, this was primarily used for short distance flight and hovering. It remains unclear if this system could sustain long distance flight.||Ant-Man (film)|
- Appearances of Yellowjacket's Suit
- Minor Appearances of Yellowjacket's Suit
- Media Yellowjacket's Suit was Mentioned in
- Images featuring Yellowjacket's Suit
- Item Gallery: Yellowjacket's Suit