To get Mechas. You need to use the “Mecha Support” Ability which can be unlocked by beating the Intro field a Total of 8 Times. If you do it again you get the “Field Booster”. But if you want to know how to find Mechas. Just go to Certain Robot Masters and Suffer Trying to get Sniper Joe in the Bonus Field. (I sware it will take forever) Also the Beak Enemy can be obtained in Final Destination I

The ability has a Chance of working so don’t complain it doesn’t work

Through calculations I was able to figure out all of the Mechas that appear by chance:

The nitron trio appears at the reflection chamber

So far the Nitron R has been encountered 2,520 times making it the most common of the trio.

The Blue variant has 995 encounters which, through calculations appears at about a 39.484127% chance.

The Yellow variant has 632 encounters. From the number of encounters it's the rarest of the trio appearing at about 25.0793651%.

I saved the best for last.

The Sniper Joe is the rarest mecha of all currently standing at 940 and has been scanned 276 times. Compared to the Met (136,132 encounters, 3,641 scans) the calculations are: .690506273% for encounters and 7.58033507% for scans.

Please note that these are estimates based on the current records in the database.

@GrowingDarkness : Sniper Joe is the only one I don't have (I got the yellow Nitron on my first try on the Fusion fields as well for the blue nitron on my first try on reflection chamber)

Is it possible to summon the Nitrons and the Sniper Joe?

@GammaGhost : W h o    k n o w s ?

The nitrons are summonable. The Sniper Joe has 0 summons, however. I guess Sniper Joe cannot be summoned.

I thought as much...

Hey look I summoned a Sniper Joe! (Jk you already know that)