Shiny Pokémon are the gold dust of the Pokémon series; via normal gameplay, the chances of encountering one are shockingly slim: 1 in 4096 by default. In case you’ve never had the fortune of seeing a Shiny Pokémon, there’s a tourist in the Seafolk Village Pokémon Center, near the café, who can fix this for ya.
He’ll battle you with a Level 55 Shiny Exeggcute. Afterwards, you won’t receive his Exeggcute (who would give away their Shiny Pokémon for free?!), but instead you’ll be rewarded with 6 Nuggets. If you want to get a Shiny Pokémon for yourself, you’ll need to get really, really lucky–or work really, really hard!
In regions other than Alola, Ride Pokémon aren’t a thing and, instead, trainers use Hidden Machines (HMs) to travel around or deal with obstacles. Despite their clunkiness, some HMs were useful for teaching powerful moves to Pokémon–most notably Surf and Waterfall. Fortunately, there’s a way to learn these particular moves.
When it’s convenient, travel towards the eastern exit of Poni Breaker Coast, ideally by flying to the Ruins of Hope and heading west. Near the exit, you should spot a pair of swimmer girls who weren’t there before. Speak to them and, after sharing their life story, they will request a battle.
Swimmer Girls Kylie and Ashlyn
This is a Double Battle with two fairly average Water-types. Lumineon can only use Surf, which hits all targets, including Lanturn. Meanwhile, Lanturn can only use Waterfall, which may cause a flinch, and has Water Absorb to heal HP from Surf. Grass-types are highly recommended.
Entertain the ladies and you’ll receive their precious TM98 Waterfall and TM94 Surf. Water-type physical attackers will love Waterfall, although they may be able to learn Liquidation from the Battle Tree Move Tutor. Meanwhile Surf can be useful during Double Battles, whereas Scald is the better defensive option.