Not much is known about the history of this incarnation of Jack Power/Mass Master prior to his first appearance.

He is the second son and third child of James Power and Margaret Craig. He is 10 years old[2], which means he was 9 years old when he received his powers from Aelfyre Whitemane [3]. This makes Jack at the moment 2 years older than his Earth-616 counterpart was upon receiving his powers.

Brash and ornery, Jack Power is the "wild child" of the Power siblings; probably even more so in this reality than in Earth-616. He frequently insulted and argued with both his teammates and his adversaries and can be very stubborn. He is however good friends with Franklin Richards, with whom he shares a taste for causing mischief and having adventures. Jack is a great fan of the Japanese Game Show "Ninja Master", and once signed up his brother Alex for this show. He also likes to make videos about the teams' training sessions.[4]


Primarily, Jack has the ability to control the density of the molecules of his body. He can disperse his molecules into a dense, cloud-like form, or reduce the space between them until he is a small, highly resistant 8" size. He has also shown the ability to materialize only a portion, or just a part of his body, like making his upper body solid while his lower half stays in cloud form.

In Earth-616, when his sister Julie had the powers as Molecula, she discovered that she could also assume an 8' form that was nearly intangible. It is unknown if Jack of Earth-5631 ever had this degree of control, or if he ever switched powers with his siblings like his Earth-616 counterpart did.

Strength level

Normal human child with regular exercise.


Power Pack Uniforms

Discover and Discuss


Like this? Let us know!

Community content is available under CC-BY-SA unless otherwise noted.

Fandom may earn an affiliate commission on sales made from links on this page.

Stream the best stories.

Fandom may earn an affiliate commission on sales made from links on this page.

Get Disney+