The Black Rope is a mysterious cursed tool imbued with a curse with the ability to disrupt and cancel out the effects of other cursed techniques. It was apparently woven by Miguel's clan of sorcerers in Africa over the course of several decades.
As a cursed tool infused with a cursed technique, the Black Rope's strength is comparable to special grade cursed tools. However, rope burns away every time its own cursed technique is used, making it smaller with every hit until nothing is left.
Miguel was in possession of the Black Rope during the Night Parade of a Hundred Demons. As one of Suguru Geto's strongest commanders, Miguel was chosen to hold off Satoru Gojo in a jujutsu battle. Miguel used the Black Rope to disrupt the effects of Gojo's Limitless jujutsu. The Black Rope effectively nullified the Infinity, allowing Miguel to hit Gojo's body with physical attacks, something most of Gojo's adversaries can't accomplish.
However, shortly after the start of their fight more than half of the rope was burned away from being used. Miguel complained to Gojo that it took decades for his people to weave the Black Rope, but Gojo didn't seem to care. The curse user stalled Gojo for another ten minutes and escaped, but all of the Black Rope in his possession was destroyed.
In preparation to stop Kenjaku's evil plot on Japan, Tengen mentioned that the Black Rope had the potential to cancel out the effects of Prison Realm and free Satoru Gojo. When Miguel returned to Africa to train Yuta Okkotsu, they visited Miguel's village elder in search of the remaining Black Rope. However, it was a fruitless effort. Unfortunately for the jujutsu sorcerers, there wasn't any of the rope left.