Hua Qi (花器) or Fang Sheng Qi (仿生器) is a special category of Yixing Zisha, it refers to the teapots created in the shape of fruits, plants (typically like bamboo), animals etc., in realistic style. A good Hua Qi is a real artwork, it combines sculpture, carving and the utility of tea brewing.
 
This pumpkin pot is an excellent sample. Its main material is gritty Duanni clay, which displays a vivid texture of pumpkin; then the body, except the leaves (spout & side decoration), the vine (handle) and the pedicel (knob of lid), is coated with Zhuni clay, to show the color of a mature pumpkin; all the realistic details bring out the smell of late autumn; as a teapot, it is very light, easy to handle, and pours out very quickly and smoothly.
 
The photos were taken under natural light and not edited. There may be subtle nuance when you see the teapot under different lighting.