YMMV / Pokémon Infinite Fusion

• Awesome Art: Plenty of the custom sprites, particularly those that go above and beyond combining the traits of both Pokémon. Special mention goes to Butterfree's Palkia fusion, giving its wings a highly detailed cosmic appearance that is incredibly done via pixel art.
• Annoying Video Game Helper: Erika when she's your partner in the Celadon Sewers. If you're trying to capture the wild Pokémon in the area, she's gonna make your efforts incredibly difficult due to defaulting to attacking said wild Pokémon, which is especially bad if you're doing a Nuzlocke or you find a shiny Pokémon.
• Creepy Awesome: Duskull is famous among the fandom for its incredibly badass fusions, usually taking the form of what is essentially an undead version of the other Pokémon. Its evolutions get some gems as well, such as Dusclops/Torterra ^note an undead-looking Torterra with a black-and-red Creepy Cathedral on its back and Dusclops' eye hovering above it like a moon and Lanturn/Dusknoir ^note a blue Dusknoir with its Belly Mouth full of Scary Teeth like a realistic anglerfish.
• Game-Breaker: The ability to fuse certain mon naturally leads to some degenerate combinations, especially when it comes to certain insanely powerful moves and abilities that are restricted by their availability to only a select few Pokémon that can't utterly break them. The No Guard One-Hit KO loophole has been the subject of an Obvious Rule Patch, but many other wild combinations remain.
  • Breloom and Parasect are both available... as are Klefki, Cottonee and Whimsicott. If the thought of finding yourself on the receiving end of a Prankster Spore does not send a chill down your spine, you are a braver man than most. Smeargle is available too, letting you create any degenerate setup you desire with Prankster to back it.
  • Slakoth is available fairly early, and Slaking is a monstrously powerful Fusion component since it can avoid being weighed down by Truant. Fantastic fusion partners for Slaking include Machamp (giving you your choice of No Guard for 100% accurate Dynamic Punches or Guts for even more raw power) and Azumarill (giving you Huge Power, running off an already impressive 123 base attack, although it takes some slight Loophole Abuse).
  • Shedinja has a fantastic ability in Wonder Guard but is held back by its typing giving it a ton of exploitable weaknesses (not to mention the slew of other ways to get around Wonder Guard). While the way Shedinja fusions work makes it impossible to create either a Sturdinja or a bulkier mon with Wonder Guard, you can give Shedinja a typing that makes it much harder to kill. Good candidates include Dark/Ghost (weak to only the fairly uncommon Fairy type) or Bug/Steel (weak only to the Fire type, which is more common than Fairy but compensates by being immune to poisoning and Sandstorm, two other ways a Shedinja can easily bite the dust).
  • Volcarona is a powerful Pokémon normally available in the late game or post-game, but here it's a static encounter in the Safari Zone's desert temple. While Volcarona doesn't really need any help to be strong, one fun thing you can do is fuse it with Togekiss, getting access not only to the Serene Grace Air Slash flinch shenanigans Togekiss is infamous for, but also to a Fiery Dance that is guaranteed to raise the monstrosity's special attack.
  • Yanma can be obtained through an NPC trade in Cerulean City. Combine Yanma with a Pichu that learned Nasty Plot (which boosts special attack by two levels), then evolve the Pichu side into a Pikachu. The result is a devastating special sweeper that can combine Electro Ball (a Special move that deals more damage the faster you are compared to your target), a paralysis-causing move to halve the target's speed, Nasty Plot, and the ability Speed Boost (raises speed by one level every turn) to quickly become too fast to stop. Even with a low base stat total, such a combination will carry you through the game. Once you fully evolve it... it will start sweeping teams with neutral or even resisted damage.
  • Fuse something that can learn either Shell Smash or Quiver Dance with Mimikyu. You get a free setup turn thanks to Disguise negating the first attack that hits it, and at least two if the enemy uses a status move (and so on). Setup and sweep away.
  • Blissey/Dusclops is able to pair Blissey's colossal HP stat and its very high Special Defense with Dusclops' equally good physical Defense to produce a formidable Stone Wall with three immunities that can soak up hits and (thanks to Dusclops not being fully evolved) use Eviolite to boost its defenses even further. The main downside is that Eviolite only increases defensive stats by 25% instead of 50% like the official games, but the fusion's bulky enough for it to not make much of a difference.
  • After you kick Team Rocket out of Silph Co., the receptionist will sell various items produced by the company at a discount. While most items are fine, the discount on DNA Reversers is great enough that they can be resold for a profit at a regular Pokemart. This effectively renders money an infinite resource, with it being possible to reach the cap in a matter of minutes even with very little starting capital.
• Good Bad Bugs: Inspecting the game's various trash cans in version 6.0 onwards occasionally yields an encounter with Trubbish or a fusion with one. Prior to version 6.1, this included the trash cans in the Vermillion City Gym puzzle; as there's nearly twenty cans and the nature of the puzzle means it resets and re-randomizes itself a lot, the sheer number of trash cans checked while trying to solve it resulted in lots of people getting unexpected Trubbish encounters in the Gym.
• Hilarious in Hindsight: This game allowed you to make a fusion of Gallade and Gardevoir before Scarlet and Violet introduced a human-made fusion of the two, Iron Valiant.
• Moe: If you fuse two Pokémon that are considered this trope together, there is an incredibly high chance that the result will also qualify for this trope.
• Self-Imposed Challenge: A popular one is completing the game with a team consisting entirely of fusions of one particular Pokémon.
• Sidetracked by the Gold Saucer: The title screen shows two random Pokémon, followed by their fusion, then another random pair, repeat ad nauseam or until you open up the main menu. It's easy to get distracted looking at the random fusions and trying to guess what they'll make.
• Tear Jerker: Fusing Kangaskhan and Cubone results in a very sad look, regardless of order. While Kangaskhan/Cubone is the baby Kangaskhan alone wielding a bone with a sad look on its face, Cubone/Kangaskhan is a mother Kangaskhan in tears, with visible cracks on her head and a dead baby in her pouch. At the very least though, both get better when the Cubone evolves; Kangaskhan/Marowak becomes a young Mega Kangaskhan, and Marowak/Kangaskhan/Cubone has a baby Cubone in the pouch alongside the now-armored mother Kangaskhan.
  • Fusing Cubone with Marowak gives you a Cubone crying over its dead mother's skull.
• That One Boss:
  • Koga's post-5.0 Classic Mode battle has gotten this reputation thanks to his ace, a Chansey/Muk fusion that uses its halves' combined bulk and Black Sludge to tank hits while it uses Toxic to stall out its opponents. Add in Acid Armor and Minimize to increase its survivability even further, and you have a Stone Wall most trainers won't have an answer for the first time they fight it.
  • Zapmolcuno is an absolute monster when you fight it in Mt Ember. You see, the three heads of the fusion all count as individual Pokémon that act on their respective turns, as if you were in a triple battle, but you, on the other hand, are only allowed to send one Pokémon out. This means that all three heads are free to turn their attacks against it and, given their legendary-level stats, probably destroy it. In case you thought you could waste them all with a well-placed Rock Slide, they all come with berries that reduce the damage dealt by super-effective attacks. On top of everything else, the Articuno head has a chance to use Tailwind. If that happens, Arceus has forsaken you, all three heads will outspeed everything you send out and grind your team into dust before any of your remaining Pokémon even get the chance to act. Giovanni was right - the world would not have stood a chance before such a monstrosity.
    • Paldiatina, fought atop Mt Silver, functions the same way, and each head has legendary-level stats and incredibly powerful attacks to throw at your party. No wonder even Cynthia was terrified at the mere idea of facing that thing. Thankfully, at that point, you have a much wider selection of Pokémon to choose from, including many Olympus Mons of your own (and the Shedinja fusions mentioned in the Game-Breaker section can wall it completely).
• That One Sidequest: Thanks to the introduction of Meloetta and Cresselia, the game introduced two new quests, "Mysterious Lunar Feathers" and "A Legendary Band":
  • In order to start "Mysterious Lunar Feathers", you need to go to Lavender Town's orphanage with negative karma. This will spawn a lunar feather at night, which makes an entity speak to you. The next thing to do is to collect five lunar feathers that will appear at night, all while shadow figures will tell you where to go. The problem with the first half of the quest, is that you need to figure out which town the clues lead to, enter the building that has a bed with a lunar feather on top of it and get it (one clue also mentions a playground, when you're actually supposed to know that the second feather is at Cerulean's Daycare). Once you get the fourth feather, you have to go back, and once the fifth feather is collected, you can sleep in the bed to go to Halfmoon Island, to either side with Darkrai or Cresselia, and complete a minigame based on your choices.
  • "A Legendary Band" relies on a new mechanic that got introduced in the game: the days of the week. To start the quest, you have to go to Saffron City's nightclub during Saturday to listen a performance, wait until it finishes at 8PM, and then talk to the organizer, where one of the singers mentions drumming sounds coming from Crimson City. Once you find Lycantillery and fight it once you come back, the next few steps of the quest have you seek out the remaining band members Wigglytop, Oriwak, Altaroc and Treno, with the organizer telling you when to find them. Wigglytop is easy to find on Friday at the Goldenrod Tunnel, after giving them at least 5000 pokémoney; Oriwak is at a new section of Treasure Beach, and will appear at 5PM on every Wednesday; Altaroc requires you to head to the new area of Mt. Moon during Monday morning, and perform an annoying cloud parkour, and Treno can only be found on a new section of Ilex Forest during Tuesday night, where you have to be careful to not scare it. Once you get the last member, you have to come back on Saturday night (which luckily, the bouncer will allow you to enter, since you helped the organizer), and once you attend the concert, Meloetta will appear.
• Underused Game Mechanic: The Karma system is an interesting mechanic, as it allows the player to gain or lose karma, based on what they do (helping people with their quests, for example, gives you positive karma, while buying Pokémon from Celadon City's Team Rocket black market gives you negative karma). However, aside from a sidequest that allows you to obtain Darkrai and Cresselia with negative karma and a random event where Mew will spawn at a certain location if you have positive karma, the karma system isn't used anywhere else.