Golu's encounter with animals
Golu, the protagonist, has seen various animals in his life. However, there are certain animals that he has never come across. Among the given options, the animal that Golu has never seen is a crocodile.

Explanations:

Crocodile:
- Golu has never seen a crocodile. This may be due to the fact that crocodiles are not commonly found in the area where Golu lives.
- Crocodiles are large aquatic reptiles that are typically found in tropical regions. They are known for their long snouts, powerful jaws, and scaly bodies.
- These creatures are often found in rivers, lakes, and swamps. They are skilled hunters and can be dangerous to humans and other animals.

Python:
- Golu has seen a python. Pythons are non-venomous snakes that can be found in various parts of the world, including tropical regions.
- Pythons are known for their ability to constrict their prey. They are capable of swallowing animals whole and can grow to be quite large.
- Golu may have encountered a python while exploring the wilderness or visiting a zoo.

Mynah:
- Golu has seen a mynah. Mynahs are small to medium-sized birds that are known for their ability to mimic human speech.
- These birds have distinctive black feathers and bright yellow beaks. They are often kept as pets because of their entertaining vocal abilities.
- Golu may have come across a mynah while walking in a park or visiting someone who owned one as a pet.

Fish:
- Golu has seen fish. Fish are aquatic animals that can be found in various bodies of water, including oceans, rivers, and lakes.
- There are thousands of different species of fish, each with its own unique characteristics and adaptations.
- Golu may have seen fish while swimming in a river or while visiting an aquarium.

In conclusion, out of the given options, Golu has never seen a crocodile. While he may have encountered pythons, mynahs, and fish in his life, crocodiles are not commonly found in his area.