Quenepas (KenEPahs) This fruit grows on a woody plant. The fruit has a brittle-leathery  shell-like skin that pops open to reveal a hard yellowish seed covered with a sweet/sour layer that tastes a little like lime. The only way to eat it is to pop the whole seed into your mouth and scrape the limey-flavored flesh with your teeth. 
In India, Quenepas are compared to Lychees.