One day you're planning to level up to unlock a certain combat skill. You ended up planning to kill the slime boss because it drops lots of EXP and is quite easy to kill. And its because you need the item the boss drop for enchantment.

After a short time going through the path to the slime boss you're already prepared and is about to attack. Suddenly the slime boss exploded and defeated right in front of you and someone stole the boss item

"Thanks for being the slime distraction"