Most warping:
In my opinion the undesputed best Pokemon from all the legal CAP Mons in this Metagame. It is literally a custom Pokemon, it has everything what a Pursuit Trapper always wanted. Great Attack statof 122 witha solid Speed of 95 for a Suiter. Thanks to that, it isn't reliant on Choice Item to further boost one of those Stats. Instead it most commonly opts to run Assault Vest it gets absurd bulky and easily tanks Hits like Focus Blast and will only get 3HKO by weaker effective special attacks at best. I should mention that with Guts you can't even get around with Will-O-Wisp and Toxing it to put on a Timer always comes with a great risk for doubling it already dangerous damage Output. So, it denies nearly alone all fraile and Status Reliant weak to Dark-Type Attacks Pokemon in the Metagame. On top of that it can also be used as solid Rapid Spiner since it can Knock of Rocky Helmet User which Excadrill only wishes in their dreams. Other Options like Sucker Punch or more niche like Aqua Tail, Crunch or a Leftovers/Dark Glasses or Greed Flame Orb can be runned but the most warping Set is the AV one which makes every Pursuit and Status Reliant Pokemona much more difficult time to use.
Tl;dr
All Special Attacker and Dark-Type Weak Pokemon might fear getting trapped or chipped for greatly damaged. It also serves as a Removal Option which ORAS lacks heavily.

To clarify, I am only gonna talk about the non-Mega Variation of this Pokemon since I think it is much more superior. I think the Mega struggles not being able to keep rocks up ever vs drill and offensive Sets being outclassed by Mega Diancie. While I do believe Coil with Double Stabs and Wood Hammer has it place in the Meta since it can solo Teams on it is own. Back to Crucibelle especially the Choice Scarf Sets shifts the whole Metagame of ORAS with being to outspeed everything witha Base Speed of 104. With acess to U-Turn it fullfills a great role of a Pivot. It also is a Poison Type which is incredible since ORAS did not have many viable ones and flexibles to begin with.Other two huge aspects of it is the abbility to threaten Clefable and walling non Twave Sets and depending on Matchup non Knock Off for Years thanks to Regenerator recovering all the Chip. Also being able to live HP Ground once from Volcarona and basically always forcing it to run Ground as the Choice of the Hidden Power make other Counter more reliable. If you would not like to hit on the Switch instantly, you are getting outspeed in return thanks to Choice Scarf and threatened by Stab Rocks Type Attacks. Not only Volcarona but also slow Setuper must fearpotential Trick and beinf crippled that way. A set with Black Sludge can be runned instead to threaten Trick on Excadrill or other Steels to make a Stealth Rock Set more viable.
Tl;dr:
Crucibelle matches well into Tspikes and more Offensive Teams nicely whiel providing overall a good pivot
Other Cap who need to be prepped for (A- or higher):

With the loss of Focus Blast it lacks sheer power it needed to hit. The Specs Set suffers from Protect Spam and the Life Orb Set end up missing crucial damage. Unlike Keldeo who is very similair with great Typing and Damage Powerhpouses to Kerf it offers 0 Utility with their Attacks unlike Keldeo's Scald. It shines best loading into Fairy Resist Clefabale + Excadrill which some ORAS OU Teams have. The insane speed tier of 119 makes lot of the 100-110 Mons lot weaker and Fodder for Kerf
Flying Type with non Rocks Weakness, beating both good Spinner and making Drill live harder with Helmet. Prankster and Intimidate are both good options depending what u want it to do and has Spin. Best Lop pivot thanks to Intim + Helmet and Taunt helps vs slower Mons. Best Sleep Pick defensively. Prankster + Haze invalidates a lot of Setup Sweeper entirely, which gives it a defining role + the Helmet Intim Set

Heart Swap underated utility with the great Bulk. Hazard + Burn/Tox immune is very cool with Magic Guard and good Typing. Dies to Knock Off unfortunate but has insane Bulk with high 151 hp base

Nice dogfish matchup fish Pokemon with Geomancy and Shell Smash. EIther 6-0 matchup or u play with 5 Mons. Needs correct moves and correct Set to win or might end up getting walled / Statused / Prio Attack.