Blackwhip

Blackwhip is the Quirk used by a previous holder of One For All and was passed on to Izuku Midoriya.

Description
The original user describes Blackwhip as a top-grade Quirk. It grants the user the ability to produce black tendrils from their arm and command them at will. It appears to be useful for capturing enemies and increasing one's own mobility by grabbing onto objects.

Usage
By the time Izuku acquires this ability, Blackwhip has evolved within the core of One For All. When Izuku focuses on capturing a target and gets angry, this power explodes out of his arm. The black tendrils are much larger and powerful enough to cause Izuku great pain and force him into submission. The tendrils easily whipped Izuku around Ground Gamma and destroyed a number of its structures.

Later when Izuku used the Quirk again to grab onto some pipes that were going to hit him, he found he could only use the Quirk for a brief amount of time because of how powerful it had become due to One For All. He was left with a numbing pain after using it.

Recently it has been shown that Izuku is able to use a less powerful and smaller version of Blackwhip without any physical strain, as long as he stays calm while using it and doesn't go over five percent of his power.