When people look at the Pokemon Paras, they think the two cute little mushrooms on it's back are just adorable little extra pieces of design. But NOPE. The mushrooms are parasites feasting away at the Paras, and when it evolves into Parasect, the mushroom fully consumes the Pokemon, and is now under the mushroom's the control. This explains why Parasect has a lack of pupils in it's eyeballs.