What went in the orange cylinders from Mars Mission? While sifting a bin of LEGO's that I received as a gift I found this strange orange cylinder:



I was able to determine that it was part 58947pb01, the "Cylinder 9 x 4 x 2 Tapered with Flat Bottom, Pin Holes with 'HIGH RISK AREA' and Captured Alien Pattern (Sticker)".  It turns out to be from the Mars Mission theme, and appeared in six sets in 2007-2007.  I'm guessing this one came from 7694-1: MT-31 Trike:



As you can see the tube forms the spine of the trike and it has something in it.  Despite consulting the instructions and watching weird youtubes that turn out to be unrelated I still have no definitive idea what the things in the tube are.

Do you know how you were supposed to play with this?  What went into the orange tube?
I'd assume from the partslist this guy is in the tube:

https://www.bricklink.com/v2/catalog/catalogitem.page?M=mm001