As a Pokemon capable of utilizing Stealth Rock and Spikes at once, especially backed by Sturdy, Crustle is a natural choice for a dual entry hazards lead. While such a set faces competition from Smeargle, Crustle retains certain perks that make it worthwhile for this role. One of the most significant of these is Crustle's significantly better maneuverability as a hazard setter; while Crustle can similarly ensure multiple layers of entry hazards by merit of Sturdy and Custap Berry, its superior bulk makes it capable of setting up later in a game if need be, making it less reliant on the first few turns of the game to accomplish its goal. This gap in bulk also makes Crustle far more resilient to multi-hit attacks, with Pokemon such as Cinccino and Rhydon becoming far less effective at restricting the amount of entry hazards it can set up. Furthermore, Crustle's better offensive presence allows it to immediately threaten other leads in a way Smeargle simply cannot, such as Scolipede.
Thanks to the combination of Sturdy, Custap Berry, and solid natural bulk, Crustle is typically capable of setting up two layers of entry hazards in most games; most defensive Pokemon cannot shut down Crustle without putting it to sleep immediately, and most offensive Pokemon either fall short of 2HKOing Crustle or put it into Custap Berry range in doing so, allowing it to pick up another layer of hazards. While typically reserved to setting up entry hazards, Crustle's ability to attack on its own should not be overlooked. For instance, Crustle's Rock-type STAB moves allow it to effectively prevent Cryogonal from spinning away its entry hazards, as well as generally damaging less bulky Pokemon. For this purpose, Rock Blast is typically the most useful option, as on top of being accurate and moderately powerful, it is also capable of breaking through Substitute and Focus Sash, allowing Crustle to better take on overzealous Substitute users and leads. Stone Edge, while not offering the same utility as Rock Blast, is significantly more consistent in its damage output, which can prove indispensable in acquiring chip damage on Pokemon. In terms of coverage, X-Scissor is often the most consistently useful, as Bug-type STAB allows Crustle to deal significant damage to Slowking, Tangrowth, and Uxie while maintaining reasonable neutral coverage overall. However, Earthquake achieves near-perfect neutral coverage alongside Crustle's Rock-type STAB and also allows Crustle to better chip away at Pokemon such as Golurk and Qwilfish, which Crustle will encounter somewhat commonly in the lead position.
220 HP EVs puts Crustle at a total HP stat that is divisible by 16, which allows it to more easily bring itself into Custap Berry range through residual damage. For example, three consecutive switch-in's worth of Stealth Rock damage will bring Crustle into Custap Berry range, allowing it to make better use of the item should it attempt to preserve itself beyond the first few turns of the game. This investment in bulk, alongside the additional 20 Defense EVs, allow Crustle to avoid being KOed outright by attacks such as Cinccino's Rock Blast, specifically avoiding the 2HKO from Golurk's unboosted Earthquake, a common opponent to a lead Crustle. The 44 Speed EVs allow Crustle to outpace minimally invested Tangrowth, allowing it to either set up another layer of entry hazards or X-Scissor Tangrowth before being put to sleep. The remaining EVs are pooled into Attack to make the most of Crustle's moderate offensive presence. One might consider investing solely in Speed and Attack, given the nature of the set, as it would theoretically allow Crustle the opportunity to set up hazards more effectively against slower teams and consequently bring itself into Custap Berry range more consistently. However, it should be worth noting that given how the metagame tends to favor bulkier Pokemon, it is more likely for the extra bulk to benefit Crustle as a hazard setter under most circumstances.
As Crustle is primarily functioning as a lead, it doesn't exactly mandate any specific partner Pokemon, though there are certainly solid options for taking advantage of exactly what Crustle brings to the table. The most significant of these options is a spinblocker; as Crustle has no method of directly preserving its own hazards, it is very important to retain the option of preventing Rapid Spin. The most common choice for this role is Rotom, as it is both capable of immediately threatening Kabutops (the most consistent Rapid Spin user in the tier) and generating entry hazard damage with its reasonable offensive presence and access to Volt Switch, though alternatives such as Spiritomb, Misdreavus, and even more offensive variants of Golurk are usable as well. However, given the efficiency of the Rapid Spin users of the tier, it is worth planning one step ahead and utilizing a Pokemon capable of following up that spinblocker and pressuring the spinner in turn. Pertinent examples of these include Durant, Gallade, Manectric, and Sceptile, though various fast Pokemon with relevant coverage options can fill this role comfortably. Ultimately, partners capable of capitalizing on the Spikes support provided is one of the most crucial of partners. Normal-types, such as Tauros and Swellow, benefit greatly from Spikes, as many of their common checks and counters are affected by them.
