How to make a advanced rig for tree roots

[rohananima]

Please help ! its urgent!

These roots are going to be used for a shot where its pulling legs of the victims in a haunted and spelled jungle.

Roots should stretch immensely, Twist and also should behave like a Ik Fk spine. 

Iam working in maya. but i am open to any softwares. 

[parzival-roethlein]

in this demoreel you can see a root rig breakdown, starting at 0:30

looks like spline-iks to me and some layers of control, from global down to each joint. the option to blend the parent controls and stretchy. you probably have to find a good twist control (advanced twist, or work with the twist attribute on the splineIk)

i also recently made a joint chain rig comparison on my blog, maybe that is helpfull for you: http://pazrot3d.blogspot.com/2012/11/joint-chain-rigging-techniques.html