Dragon Quest came up with a kooky idea for an enemy; one of the run-of-the-mill slimes but coated in metal. This increases their defense tenfold, but managing to slay one would net a heavy chunk of experience. Unfortunately for the player, metal slimes of all types tend to be skittish, dashing off more often than not. And it can be incredibly frustrating! ESPECIALLY when you meet some of the more complex cousins of the original, like my recommendation this go-around, the mighty Metal King Slime.
Beating a King will net you an amazing EXP payload; 30010 in the majority of its appearances. However, you have to slowly pick away at its metallic exterior in order to score that hefty reward, and with 7 – 20 HP (depending on the game), you will likely have to rely on characters with high crit/low hit moves in order to destroy them before they scamper out of the battle. But the sheer thrill of actually connecting such a blow and blasting through their high defense to instakill them is one that is nearly unrivaled in any RPG. It’s sensationally sweet.
So while the entire metal slime family can cause a plethora of pissiness, there’s nothing quite like that moment where an insane risk pays off and you see your characters receive massive gains. And for that, I find them among the best enemies in any game, particularly the Kings.