Shadow Excadrill

Shadow Excadrill is an easily overlooked Pokemon, but its performance is stellar in its own right. It has outstanding potential damage output, and a typing that shields its lower base-bulk and makes it surprisingly bulky depending on the raid.

Best PvE Offensive Moveset

• Mud Slap is preferable since Shadow Excadrill is primarily used as a Ground-type attacker.
• Mud Shot falls behind in performance due to inferior damage output. 
• Metal Claw in a nutshell performs better from a stats perspective, but isn't as useful in practice. 
• Scorching Sands is definitely Shadow Excadrill's best Ground Type move.
• Earthquake is stronger than Drill Run, but the later is more reliable due to being 2-bar. 
• Iron Head can pair with Metal Claw if a Steel-type attacker is needed, but Shadow Excadrill isn't the best for this role. 
• Rock Slide lacks STAB and has little use. 

Best PvE Defensive Moveset

• Mud Slap is superior to Metal Claw on defense thanks to its significantly higher base power. 
• Mud Shot has poor damage output for defense. 
• Iron Head sports the earliest damage window, and is the hardest to dodge. 
• Rock Slide doesn't get STAB, but it is hard to dodge and offers greater coverage. 
• Scorching Sands works well on Defense.
• Drill Run is a bit slower than the others, but still performs okay on defense.
• Earthquake is too slow for defense. 

Mud Slap is preferred over Mud Shot; its massive damage output is generally worth it over Mud Shot's slightly higher energy gain but far worse damage output. Metal Claw is an underwhelming move for PvP, and Steel-type coverage is typically not as valuable. 

Rock Slide ties for the least amount of energy, and provides wide coverage. Drill Run is an efficient move that is recommended over Earthquake due to significantly less energy costs. Scorching Sands is weaker than Drill Run and has a higher energy cost, making it a lesser option. However, it also has a 30% chance to debuff the target's Attack, so it's not entirely outclassed. Iron Head is typically not used due to other charge moves being more valuable.