Slaking had a base stat of an amazing 670 and it's not even a pseudo legendary,I consider having Slaking kind of unfair,it's pretty hard to take out,that's why Norman is the only gym leader I lost to,even when I had a Combusken at level 33.
If you're nor prepared, you're up against a formidable gym leader. He might be your dad (in the game ) but his Slaking's moves are almost competitive level. Yawn is an annoyance and his Façade , attack is a wild STAB moves
i always found Norman to be one of the hardest gym leaders. he is much MUCH worse than Whitney based on my experience and im not one of those people who overlevels their starter, but uses a balanced leveled team
My gowd, level 39?? I've been grinding my pokemon to level 30 and it's tough before passing gym Norman. Pokémon arounds are only around level 15-20ish. Daily grinding do get boring
Norman: "Hm... So, did you get four Gym Badges. Fine, as I promised, we will have a Pokémon battle. Trainer... I'm so happy that I can have a real battle with my own child. But, a battle is a battle! I will do everything in my power as a Gym Leader to win. Trainer, you'd better give it your best shot, too"!
The fifth gym leader is your father, Norman, the Petalburg City Gym Leader. He has 2 Slaking, and Vigoroth. If you defeat him, he'll give you the Balance Badge.