After your quest at the Spear Pillar, return to Lake Verity and go into its cavern. After you interact with Mesprit, it will leave and roam all over the Sinnoh region. Use the Marking Map on the Pokétch to track the areas of roaming Pokémon. Once you’re at the area where a boss symbol is marked, you’ll encounter the roaming Pokémon. Mesprit is on Level 50. Remember, roaming Pokémon flee on the first turn. If you still have the Master Ball, it would be the time to use it. Otherwise, have a Pokémon that knows Mean Look then use Dusk Balls when battling at night. ... https://www.youtube.com/watch?v=thhL_FJasf8

Between 3:00 P.M. and 4:00 P.M., go to Blue’s house in Pallet Town and Daisy will give a massage to your Pokémon, but only if it has max happiness. She can massage your Pokémon once per day. After she gives your Pokémon a massage 5 times, she will give you Blue’s phone number on the PokéGear. Call Blue on a Sunday night and he will be at the Fighting Dojo in Saffron City. Exeggutor will lead off by using Trick Room that inverts the speed order for all combatants for 5 turns. Machamp will use Fling to throw the Iron Ball it holds and Dynamicpunch to confuse the target. Rhyperior will use Stone Edge to more easily land a critical hit and Thunder Fang for a 10% chance of paralyzing the target. Arcanine will use Flare Blitz to deal big damage at the cost of its own HP and Extremespeed to strike first. Tyranitar will change the weather to a sandstorm with its Sand Stream ability and use Low Kick to deal more damage against heavier targets. Pidgeot will use Double Team to raise its evasiveness stat and Air Slash for a 30% chance of making the target flinch. Think of a whole variety of moves you can use for this battle. ... https://www.youtube.com/watch?v=lMx9E7Bdi-I