Choc-ice can be bought from a local vendor named Rokuh in Nardah. They are sold for 30 coins each. When eaten, they heal 6 hitpoints, and quench a player's thirst if they are in the desert. This can come in handy as an alternative to bringing waterskins to the desert, although most players prefer to use waterskins to save inventory space.
Choc-ices were developed to aid the people of Nardah. When the town was cursed and could no longer provide water, a man bought a box of magical non-melting ice. He used this to help keep the people of the dying town hydrated. Despite this, choc-ice can melt when in the Kharidian Desert. Perhaps the ice can only melt while outside of the box.
Karamel, an enemy from Recipe for Disaster drops a choc-ice when she is killed.