23 Ultra Balls + 53 Pokeballs for Beldum.. and not works.

Beldum has like the lowest catchrate in PRO(even in the console games) Its sadly not a bug :/ the catch rate is like 0,4%ish if i remember correctly

Catching these guys is frustrating xD

Beldum have the same catch rate than Arceus, Is not a bug, is just the most difficult pokémon to catch, good luck & Enjoy

me first beldum need 150 ultraballs but you iv 30x4 xd never cath another

-Snip-

 

Pokeball has a 1% chance, Ultraball has 4% chance. It's not a bug. Here is Beldums catch rate graph in the actual games. https://www.thonky.com/pokemon/best-pokeball-catch/beldum

Beldum's are incredibly rear to encounter and catching is even tougher

Make sure to use false swipe to get it to 1HP and use sleep as status condition

 

That will increase your catch rate pretty much ^^

Hope it'll be much easier to catch next time you encounter one :)