Once you have the HM03 (Surf), you can Surf on water. Try doing this for example on Route 6 to enter the other side of the Mistralton Cave. In a deep and dark cave, an old man will tell you about 3 legendary fighting Pokémon hidden across the Unova region. One of them is inside the Mistralton Cave. Save your game once you find the legendary. Cobalion is on Level 42. Its signature move is Sacred Sword, a Fighting type move that deals damage regardless of the target’s stat changes. Since you’re in a cave, Dusk Balls would be recommended. Furthermore, don’t attack Cobalion with any Dark type move or else its Attack stat will raise with the Justified ability. ... https://www.youtube.com/watch?v=716gyyBMHeg
After you met Cobalion at Route 6, you’ll see it again as you’re almost finished exploring Route 13. Save your game before interacting. Cobalion is on Level 45. Its signature move is Sacred Sword, a special Fighting type move that deals damage regardless of the target’s stat changes. If you defeat Cobalion, you’ll have a 2nd chance later after you beat the Elite Four and it will be on Level 65.
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https://www.youtube.com/watch?v=FBwQTpqbd8A
After receiving the Pokédex at Mr. Pokémon’s house on Route 30, make your way back home to New Bark Town where Professor Elm’s lab is. As you’re about to exit Cherrygrove City going east, an unknown boy in red hair will appear. He has stolen a Pokémon from Elm’s lab, and it’s a starter that has an advantage over yours. This trainer will be your new rival. After the battle, continue back home.
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https://www.youtube.com/watch?v=qLG8vW72i-A
You’ll fall a long way down and meet some Shy Guys on the mountain. Go through the door to enter a path full of Shy Guys and Tweeters. After crossing a wooden bridge, platforms made of wood will fall from a waterfall. On the next landing, you’ll see more Shy Guys and Tweeters. Once you find a mountain, enter the door into the cave where you’ll see a Ninji. Climb the vine and turn right where the door will lead you back outside. Continue ahead and climb the vine by a Hoopster. As you scale the mountain, you’ll see more Shy Guys, Ninjis, and Hoopsters. Once you reach the clouds, climb the vine to go high in the sky to the boss area. Frosty the Snowman will shoot snowballs and you must throw them back at Frosty. After hitting Frosty 3 times with snowballs, a jewel will appear for you to pick up so the Mask Gate will open for you to go through and complete the level.
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https://www.youtube.com/watch?v=Gp2DyXf5i64
After you reach the boss room during your Area 10 adventure in the Black Tower, you’ll battle Benga, said to be the grandson of Alder. Latios will use Icy Wind to slow down opponents and Draco Meteor for massive damage while the White Herb it holds gives it a break from a lowered stat for once. Garchomp will use Stone Edge for critical hits and Outrage for powerful strikes in 2-3 turns. Volcarona will use Quiver Dance to speed up and making contact with it can cause burns due to its Flame Body ability. After winning, Benga will leave the tower and you can go to Floccesy Town to receive a shiny Gible.
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https://www.youtube.com/watch?v=5L_dmMmOjTQ
The next boss is Cractus. In super-hard mode, the timer is set at 2 minutes. Break the vase first and use the ladders to hang on until the boss comes in so you can bonk its head. If you get caught in its dribbling fluids, you’ll turn into a zombie. If you purchase a Black Dragon from the shop, you’ll inflict great damage before doing your first attack.
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https://www.youtube.com/watch?v=A7bdPidjW8U
On Cinnabar Island, get the Secret Key from the Pokémon Mansion then use it to access the gym. This gym has a puzzle with computers giving you a quiz to answer questions. If you guess a question correct, you’ll open the door to the next spot with the next computer quiz. If you guess a question wrong, you’ll be forced to battle a trainer. Beat the trainer for the door to open. After all shutters open, you’ll take on the gym leader. Blaine uses Fire type Pokémon. When Ponyta and Rapidash use Fire Spin, you can’t switch out as the move repeats itself for 2-5 turns. Their Stomp attack has a 30% chance of making targets flinch. They will also use Bounce to avoid attacks for the first turn then strike the next turn, having a 30% chance of paralyzing the target. After winning, you’ll receive the Volcano Badge and a TM38 (Fire Blast). Fire Blast is a powerful Fire type move that has a 10% chance of burning the target.
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https://www.youtube.com/watch?v=ajjE9yBjxEo
Erika is one of the Kanto Leaders in the Pokémon World Tournament that can be battled in either the Kanto Leaders or World Leaders Tournaments. Erika is skilled in using Grass type Pokémon. Vileplume will use Petal Dance with a Grass Gem in support to power it up for once. It also has a combo to use Sunny Day and Moonlight to recover more. Venusaur will use Light Screen to reduce damage from special attacks for 5 turns and Toxic to poison opponents. Victreebel will use Leaf Blade for critical hits and Sucker Punch to strike first. Exeggutor will use Hypnosis to put opponents to sleep and unleash a big SolarBeam when sunny. Tangrowth will use Swords Dance to power up and Rock Slide to make opponents flinch. Bellossom will use Drain Punch to steal HP from opponents. A move like Flamethrower will easily knock out the opponents.
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https://www.youtube.com/watch?v=TR5CUnLFwJQ
The start of the stage has ceiling hatches that drop grenades. Some spots have round ventilators that shoot fire in a circle, so they can be hard to pass. Some ventilators shoot fire only straight, so time your movements to get past them. The next area has moving platforms and floating gunners. Grab the crane to go to higher ground and electric pitches will move about. Use the hookshot to latch onto the pole above and go to the next area. Cross a spike pit and defeat some electric carts. A ceiling with spikes will close in, so you have to move fast to avoid getting crushed. Next, you’ll battle against Colonel Allen. He has a machine gun that shoots multiple rounds. Defeat him to clear the stage.
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https://www.youtube.com/watch?v=dAvZolyOqBk