The Ghost/Grass-type Pokémon, Dhelmise, is a rare spawn in Pokémon Sword and Shield. It's not obtainable in the wild until players are nearing the end game around Spikemuth, but specific Max Raid dens in the Wild Area boast a small chance of hosting a Dhelmise raid as well.
Dhelmise has a 1% spawn rate in the wild, and the chance of a Dhelmise raid cropping up isn't much better. 1% feels like a weirdly low likelihood, given it isn't an outstanding Pokémon by any means. While it boasts an impressive base attack stat, it's type combo leaves Dhelmise open to several Grass-type weaknesses. This landbound shipwreck of a Pokémon is nevertheless a unique Pokédex entry, so here's how to find it.
Overworld Spawns
In the wild, Dhelmise spawns in the overworld on Route 9, around Outer Spikemuth and down by Circhester Bay. Given its 1% likelihood of appearing, trainers will have to return to the area many times before happening across one.
To expedite this process, take a Flying Taxi to Spikemuth and scan the patches of tall grass as you head down the slope towards Circhester Bay. If Dhelmise has not spawned, just take a Flying Taxi back to the top of the hill to reload the spawns in that area. Players can also reload the area by dipping into the tunnel leading to Route 7 or venturing into Spikemuth briefly. Upon returning to Outer Spikemuth, some of the previous spawns should've switched out. Repeat this process until Dhelmise appears.
Max Raid Dens
Dhelmise raids only spawn in specific dens throughout the Wild Area. Dens in Bridge Field, Dappled Grove, Giant's Mirror, and Stony Wilderness are capable of hosting Dhelmise raids. Given the Pokémon's dismal chance of appearance, it's advisable to use a system hack to move matters along.
This method includes utilizing Wishing Pieces and adjusting Date/Time settings on the Nintendo Switch. First, save your game before this undertaking — just in case something goes wrong. Then, start by dropping a Wishing Piece to activate the Den. In the raid lobby, begin searching for other players, then suspend the game and go to the Switch's System Settings. From there, select Date/Time and fast-forward a day. Resume the game and Quit searching for players and back out of the raid. These steps reset the raid Pokémon upon re-entering the raid lobby. Repeat this process until Dhelmise appears, which can still take a while.
Dhelmise may be highly elusive and not so highly valued in battle, but it's still a fun Pokémon to use from time to time. For instance, a Dhelmise with Rapid Spin can be an infuriating foe against other Pokémon with the same normal-type move, which doesn't affect Dhelmise's Ghost-type.
For trainers aiming to "Catch 'em all," that means filling every Pokédex entry no matter the Pokémon's battle prowess. If a completed Pokédex is the goal, then definitely try the time jump or area reload tricks mentioned above to speed up the hunting process and leave less to that 1% chance.
Source: Serebii