A dark side power was used by Darth Sidious to attack Ezra Bridger and Ahsoka Tano. Manifesting initially as fire, it could serve as both a weapon and a tool in order to bind and draw someone closer, as it did with Ezra; the energy wrapping around his leg and becoming akin to a tangible rope.
The energy could also be blocked by someone powerful in the ways of the Force, as shown by Tano during her confrontation with Darth Sidious. However, the process proved extremely taxing on her as she was injured as a result of using too much energy to repel the attack. Any physical manifestations of this power can also be severed with the use of a lightsaber. Such was the case when Ahsoka used her lightsabers to cut the energy wrapped around Ezra's leg, severing his connection to Sidious and causing significant pain to him in the process.