Some Pokemon Sword and Shield have specific criteria that you must meet in order to evolve them. Clobbopus is one such Pokemon. While it is possible to capture their evolution, Grapploct, later in the game, you can also evolve Pokemon using the method below.
How to evolve Clobbopus in Grapploct in Pokemon Sword and Shield
You can catch Clobbopus on Route 9, where they will be between levels 39 and 43, or you can try your luck in a Raid Max battle in the wilderness to catch them first. To evolve into Grapploct, Clobbopus must know the Taunt move.
He would typically learn Taunt at level 35, so if you catch a Clobbopus who is taller than that but doesn't know the move, you can go to a Pokemon Center to help him remember the move. When the Clobbopus knows the move, put it in your party and you can level up until it evolves. You just have to level up once after learning Taunt and it will evolve.
If you are patient, you will be able to reach a level 50 Grapploct shortly after obtaining the Rotom Bike upgrade which allows it to travel on water. Grapploct also appears as a strong wilderness spawn in the wilderness area later in the game.
If you need more help with Pokemon Sword and Shield, we have a number of guides you might find useful. From how to use PC Box Link, how to change the nature of a Pokemon, and how to trade Pokemon. If you're looking for some of the rarer Pokemon, we can show you where to find Dreepy and Ditto too.