Monstrosity of Tendrils

Probably Urami's most powerful technique, this allows the tendrils within his body to explode out, creating a giant creature which, in some ways, resembles a dragon. This creature, although it appears to be one of his beasts, it is actually just Urami. Due to it being him, it may use any technique or  technique Urami knows, as well use it's tendrils to attack. Although it's extremely powerful, it does not require chkara (much like Urami's other hiden techniques), allowing Urami to use it until the creature uses too many jutsu.

Drawbacks
Even though it does not require chakra, it does have a weakness; Urami. Urami must be connected to the creature at all times, and may only be disconnected for no longer than thiry seconds. If he is disconnected for thiry seconds, the tendrils will immediately flow into Urami, ending the technique.

Behind the Scenes
This technique, as well as a few of the techniques I've created for Urami, is based on Kakuzu in this video (2:28).