Consequences of not paying Zakath

Narrated Abu Huraira (RA) Allahs apostle (PBUH) said, Whoever is made wealthy by Allah and does not pay the Zakat of his welath, then on the Day of Resurrecion his wealth will be made like a bald-headed poisonous male snake with two black spots over the eyes. The snake will encirlce his neck and bite his cheeks and say, 'I am your wealth, I am your treasure.'

(Bukhari)