The Massif is a Tusken pet not Geonosian.

[jedi master sal]

It took me until the sixth viewing to notice that the massiff is not a geonosian creature but a Tusken raider dog.

Notice two of them fighting over a bone (or something) just after Anakin jumps down from the cliff. One even comes after Anakin when he decapitates two of the Tuskens. (lower right corner of scene as the Tusken is running toward camera)

What a major goof on the part of Hasbro.

Now they'll go and make a Tusken w/Massiff figure.

[Lman316]

I noticed this too. When I first saw them fighting and then I didn't see them anywhere on Geonosis, I figured Hasbro made a goof.
But since then, I learned two things. One, Massifs are found both on Geonosis and Tatooine. And there was a cut scene (or something) with Obi-Wan getting attacked by Geonosians and Massifs, instead of the destroyer droids. :)

End.