Chacs looked like slender jaguars when on all fours and werejaguars when they assumed a bipedal stance. They were spirits who helped control the rains in Maztica and lived in caves high in the mountains. From their caves they sent out rain to the surrounding countryside.
A chac's colouring depended on where they lived. Northern Maztican chacs were blue while those in the east were black. Chacs from the south were red while those in the west were yellow.