Players who want to own a Metagross in Pokemon GO must first hold onto a Metang. Metang is a really rare Pokemon. The easiest way to get a Metang is by evolving a Beldum.
If trainers end up with a Metang, they'll naturally want to evolve it into a Metagross, who is one of the most powerful Pokemon in Pokemon GO. It can perform as an attacker and a defender. It's got one of the best Steel Type moves in the game, known as Meteor Mash.
Metang in Pokemon GO
Trainers must feed Beldum 25 Beldum candies to evolve it into a Metang and follow it up with 100 more candies to evolve it into a Metagross.
Unfortunately, Beldums aren't common in the wild either. The spawn rate for this Pokemon was boosted during the recently concluded Hoenn celebration event in Pokemon GO.
During the Hoenn celebration event, trainers could hatch Beldum with 5 KM eggs. But with the event done, the spawn rates have gone down by quite a notch. The Pokemon cannot be hatched with 5 KM eggs.
According to Silph Road, Beldum can be hatched using 10 KM Adventure Sync eggs. Trainers can receive this if they walk 50 KM with Adventure Sync turned on in Pokemon GO.
To increase the chances of catching these Pokemon, trainers should try using incense. This item is active for 30 minutes and can attract Pokemon to the trainer's location.
Since it's a Steel Type Pokemon, using a magnetic lure module on pokestops is also an option. Given this Pokemon's scarcity, trainers will need to rely on their luck when attempting to catch a Beldum in Pokemon GO. All of this must be considered before thinking of Metang.