Melocactus curvispinus grows individually and has a short cylindrical, dark green, slightly glaucous spherical stem that reaches a diameter of 8 to 27 centimeters in height to a height of 6 to 30 cm. It has 10 to 16 pointed ribs and sometimes slightly warty. The areolas are slightly sunken, from them spines of dirty white to almost black spines appear, some are curves. The 1-4 central spines, which may also be absent, 15 to 52 mm long. From 6 to 11 radial spines are between 3 and 42 mm in length. Cephalium is ralatively small with a height of 3 to 4 cm and a diameter of 7 to 11 cm that stands out clearly for the long reddish-brown bristles. The flowers open in the afternoon and are dark and purple, pink, 18 to 43 mm long and have a diameter of 10 to 25 mm. The fruits are pink to bright magenta red. It is known by the names of melon de monte, buche, pichigüey or pitigüey (mainly in Eastern Venezuela). This melon is used to remedy the kidneys. https://es.m.wikipedia.org/wiki/Melocactus_curvispinus
Melon of hill with a flower. 
Melon of hill with its fruit called pitiguey. 
This is its fruit called pitiguey. 
My nephew eating pitiguey. 
They can have the pitiguey inside where they see their small seedlings which are very soft and edible. 
Great