Piplup is great.Piplup may be weak with a 草 type but it's super effective with drill peck and peck.Piplup is super effective with 火災, 火 types too.As for electric types,you have to envolve piplup to learn dig.Also when あなた envolve it, あなた can learn 草 knot to beat water types so easily!Don't forget it can also envole to Emploen and learn hydro cannon!And don't for get metal claw either!Piplup is also very strong with it's torrent ability.Piplup is cute and when it envoles to Emploen,it looks tough and it may be too!Also,if あなた had a piplup, it can learn surf and waterfall when it envoles and then あなた could meet the champion!Remember,first is a bug trainer so あなた can beat with flying type moves like peck または drill peck.Next is ground which あなた can use 草 knot.Third is kind of 火災, 火 so Piplup can beat them easily with a water type move.Last, is a phychic type but I have no advice.Finally,the chamion's strongest pokemon is Milotic so あなた can use 草 knot!