If Ninjask is not trained properly, it will refuse to obey the Trainer and cry loudly continuously. Because of this quality, this Pokémon is said to be one that puts the Trainer’s abilities to the test. Because it moves so quickly, it sometimes becomes unseeable. It congregates around tree sap. Its cry leaves a lasting headache if heard for too long. It moves so quickly that it is almost invisible.
Pokédex entry #291
Ninjask in Pokémon GO
It's possible to hatch Ninjask from an egg?
No, Ninjask can't be hatched.
Which are Ninjask’s strengths and weaknesses?
Ninjask is a bug and flying type Pokémon. bug type pokémons are strong against grass, poison, psychic pokémons but weak against fire, fighting, flying, ghost pokémons. flying type pokémons are strong against grass, fighting, bug pokémons but weak against electric, rock pokémons.