The Scorpion is a Tier 3 Monster in Crawl.
When playing as the Scorpion, the Hero’s weapon plays a huge role in strategy. If the Hero has a melee weapon, use your special to create a wall of slime, then camp behind it, attacking the Hero if they try to get past it. If the Hero has a ranged weapon, use your special to attack the enemy from afar if they run, or stab them if they get close.
As a strategy to fighting the Scorpion, your weapon, once again, plays a huge role. If you have a melee weapon, try to rush down the Scorpion. If you have a ranged weapon, attack the Scorpion from afar.