There were a lot of wolves in Norse mythology and Fenrir was considered the most popular. This famous beast was the son of Angrboða and Loki and was known for being strong and badass. His other siblings were Jormungand (serpent) and Hel (the underworld goddess).
He was capable of causing massive chaos over the nine worlds of the Norse cosmos and a lot of people were afraid of him, including gods. Due to his innate strength, it was said that the gods bounded this monstrous beast with different types of magical chains.
Being chained was something that did not sit well with him. He knew he had to do something about it. He was a force to be reckoned with so the first two times that he was chained, he was able to set himself free.
After successfully breaking his chains the second time around, the gods knew they had to come up with something stronger. They asked for help from dwarves and they created something made from a variety of occult elements like fish breath, lady beard, cat footsteps, mountain roots, bird’s spit and bear’s sinews.
He was said to be tightly chained from this weird combination of stuff and was never released until he broke loose during Ragnarok (Doomsday) and got killed by Odin's son as revenge for killing his father.