I want to SOS chain a Beldum for a shiny, but Take Down is an issue. So naturally, I want a Ghost-type so it doesn't knock itself out. The issue is that I also need it to have Synchronize so that it's likely to be Adamant on my chaining Pokémon. I don't have access to Pokémon Bank, so that's a limitation, but if it's possible to do this through Pokémon Bank, I might get it.
Yes, there is. Use the following method:
- Get an Adamant Smeargle, preferably a high-level one.
- Get a Staryu with Reflect Type, get a wild Smeargle to copy it, and copy it off of the Smeargle with your one.
- Teach it Sketch again at the move relearner.
- Get a Sylveon with Skill Swap and get a wild Smeargle to copy it, and copy it off of the Smeargle with your one.
- Teach Smeargle False Swipe and a good powerful move against Beldum with the above method. Single target only, no Normal or Fighting-types.
- Breed a male Reuniclus line Pokemon with Skill Swap with a female Ralts line Pokemon so you have a Ralts with Skill Swap and Synchronize, which you train up.
- Get a Pokemon with Trick-or-Treat, Gourgeist probably.
Now we chain:
- Trick-or-Treat Beldum with Gourgeist.
- Skill Swap it Synchronize with Gardevoir.
- Then you send in Smeargle who Reflects Type to become a Ghost-type then Skill Swaps to grab Synchronize.
- Get Beldum to call a friend with Adrenaline Orb.
- KO the Ghost-type Beldum, then chain with False swipe, switching Beldum after 15 turns each so it doesn't struggle after the 20th move
This works with Jangmo-o, Bewear and Riolu too, but they have different lengths of turns. The call rate is also different, and after a 255 long chain, there is only a 18% chance of a shiny throughout the whole thing. This is a long process, so get a lot of Leppa Berries. Synchronize still works despite swapping, but this is after 3 tests, of which an Adamant Smeargle has drawn 2 shiny Adamant Riolu.
An easier way that would solve your problem is to just use Heal Pulse instead. The Ralts line can learn Heal Pulse and have Synchronise.
There are other ways to solve this problem involving Magic Guard, Skill Swap, and Role Play, but if your goal is to stop the wild Beldum from knocking themselves out with Take Down or Struggle recoil while keeping Synchronise on your own Pokémon, simply using Heal Pulse is your best bet.
If you also want to prevent them from struggling, bring along a Pokémon with a leppa berry, recycle, and fling. Munchlax and the elemental monkeys can learn recycle and fling by level up. Then you can just keep flinging leppa berries at the beldum to restore their PP.
It's only possible through Pokebank if you have a Pokemon meeting the criteria you want in another game (compatible with PB) or in the bank itself. You can't send yourself what you don't have.
Also I don't think Ghost types can have the Synchronize ability, and from checking online that seems to be the case. You might be able to hack a ghost type to have that ability, but I don't have any experience of that. The only ones listed are:
Source: Bulbapedia Synchronize Ability