Thor

The cat was sleeping, but she roused when they entered and sprang into the middle of the room. She was grey, and she was as big as a man, but Thor was mightier than any man, and he reached around the cat's belly and lifted her with both hand, itnending to raise her high over his head. The cat seemed unimpressed: she arched her back, raising herself, forcing Thor to stretch up as far as he could.
Thor was not going to be defeated by a simple game of lifting a cat. He pushed and he stroke, and eventually one of the cat's feet was lifted above the ground. From far away, Thor and Thialfi and Loki heard a noise, as if of juge rocks grinding together: the rumbling noise of mountains in pain.

[...]

"The cat whom you tried to lift was no cat. That was Jormungunder, the Midgard serpent, the snape who goes around the centre of the world. It is impossible to lift the Midgard serpent, and yet you did, and you even loosened a coil of it when you lifted its paw from the ground. Do you remember the noise you heard? That was the sound of the earth moving."