Mattel #6331 Callisto

#6331 Callisto Card Front

Billed as Major Matt Mason's friend from Jupiter, Callisto represents the toy line's first departure from science-based conjecture, to science fiction-based whimsy. 

MMM Alien Callisto

Originally found on this teal-background (or "green" as it is commonly referred) card, Callisto's packaging changed to an Orange-background card at some point, perhaps to provide more contrast to his green skin and make him more noticeable on the toy peg. The green card back indicates that the sensor hose connects to the back of the sensor when it actually connects to the bottom - this is corrected on the orange card. There is also a white-carded variation listed below. Both teal and orange cards feature photos of an original Callisto prototype (see Card Detail 1 and 2 below).


The card is full-color, process-printed and is 8 5/16" x 8 5/16" Copyright is 1968. The card reads: "Major Matt Mason's friend from Jupiter...The mysterious alien with advanced mental powers!"

#6331 Callisto Card Back

Sticker Sheet:


Mattel #6331-0920 Callisto (found in playsets)

Mattel Catalog Specifications:

(First appearance: Mattel Toys 1969 Spring Catalog Page 52)

Mysterious astronaut from Jupiter! Amazing alien joins Major MATT MASON's adventure-seeking space explorers. Transparent skull reveals highly-developed humanoid brain endowed with superior mental powers. Removable shoulder-mounted Space Sensor releases retractable Sensor Line for sampling unknown space matter. Flexible 6" figure. Hole-punch blister card: 8 5/16" x 8 5/16"
Std. Pack: 1 Doz.
Wt: 4 ½ Lbs.


John's Notes:

Callisto may be found in multiple packaging variations, within several card variations and boxed playsets. I've listed most of the card variations above. He may also be found in:

Teal Card vs Orange Card - Which was first?
There has been a lot of discussion as to which Card Background and Boot combination came out first. The consensus is that the Tall boot, Teal card was the original. This is supported by the small sticker that is applied to the backs of Orange cards, giving patent and copyright information. However, I have in my possession a Teal card with a Short booted figure. I personally think that the Short Booted figure was created shortly after the Tall booted one, and that they shared the toy shelves together, much like the Small head/Large head Major Matt Masons that were out together. I think that the molds reflect a change in product, but that the original Tall Booted figure mold was never decommissioned. 

Callisto Tall Boot vs Short Boot

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