A monster's strength cannot be judged hastily by its appearance.
The Mad Goblin Magical Potion Master, being a level 7 Silver Elite, sufficiently demonstrates the monster's extremely formidable strength, not something one can handle alone.
The reason Hang Yu could take down the Stone Demon is definitely not because Hang Yu possesses the strength to deal with a Lord.
If not for the level 8 Undead Knight attracting firepower, even with Jiang Nan the Doctor's assistance, Hang Yu wouldn't have had a chance, and the soul qi in the Summoning Talisman was so depleted that it obviously couldn't be used again.
Therefore, to deal with this guy, we must all work together!
The bosses spawned at a level 7 Goblin Shelter are not fixed; usually, there's a greater chance for a "Mad Goblin Magic-guided Master" to appear, and less so for a "Mad Goblin Magical Potion Master".
The former is weaker.
The latter is a lot more troublesome.
