Cut nori into thin long strips if not pre-cut.
Depend on the crew color you want, prepare the optional ingredients: boil the egg, puree vegetable and strain them if you dont like pulp.
Mix the optional ingredients with hot sushi rice and sushi vinegar. Combine them good and let it rest for about 5 minutes.
Lay a piece of plastic wrap onto your hand, take about 2/3 of the rice and use your hands to form a half cut-off oval or oblong.
Lay it on a flat non-stick surface or plate, and sort of knead or tuck here and there so that the head area is rounder a bit.
Take about 1/4 of the remainder and form into a short cylinder for a leg, repeat for the other leg.
Use whatever left to form into a half-moon shape and stick to the body.
Now lay the plastic wrap over the rice ball, and sort of knead the legs and oxygen tank into the body. Smudge and apply pressure gently to connect parts and smooth out the connection ridge.
Use thin strips of nori (around 1/5 or 1/6 inch) to go around the side of the crew.
Then use a thinner strip (1/8 inch) to highlight between the tank and the body.
Cut a hollow round rectangle/oblong to place in over the helmet area. Use its inner cutout to measure and cut the exact piece of any white ingredient (provolone, egg whites, fish cake...)
Arrange both onto the helmet as the eyeshield.
Tadaa, you've done! Enjoy your crew or repeat for another.