Abdullah bin Mubarak عبد الله بن المبارك · The Book on the Description of Hellfire

"Indeed a disbeliever's skin will be forty-two forearm lengths thick, his molar teeth will be like Uhud (mountain), and his sitting place in Hell will be like what is between Makkah and Al-Madinah."

'Indeed the disbeliever's tongue will be stretched a Farsakh or two Farsakh, such that the people will walk upon it."

Kal Muhl, the Prophet (s.a.w)said: 'Like boiling oil, such that when it is brought close to his face, the skin of his face will fall off into it."