Notes are included for the Green and Purple tentacle pictured.

These use standard amigurumi techniques: magic circle starts, working in spirals rather than real ‘rounds’ and invisible decreases. If you are unfamiliar with these I suggest having a look at Tutorials on:

Hook and Needles: http://www.hookandneedles.com/
Planet June: http://www.planetjune.com/blog/category/tutorials/