Blob mesh makes good jelly.

Combined with Cam's colored refraction material, you'll be set!
here's some links that might give you some ideas and help:
http://www.3dluvr.com/content/article/71/1
http://www.3d-palace.com/xenomorphic/ed ... at_gun.htm
at this place, go check out their gallery and their tutorials. I am SURE you'll find something in the gallery that rocks!
http://3daliens.com/glu3D/index.htm
also, you will find that blob mesh is VERY slow to calculate. PWrapper, which is part of Glu3D, does the exact same thing, only faster and with a bit more control. You may want to check that out, too.