You know the slowpoke well? Well right before you get to the well theres a cave you leave. If your standing infront of the well the cave is to your right. If you talk to the people they will tell you that on some nights you hear a poke'mon roar that pokemon is Lapras and you have to go there on Fridays. So when Friday comes around go to the cave and search deep and you will find it. Good luck!