Aggron

Aggron fits as both a strong wallbreaker and defensive wall in SS PU. Its STAB moves are naturally strong, and it has a fair amount of coverage and utility moves as well. Aggron's raw strength makes Choice Band sets extremely difficult to switch into and allows even uninvested variants to do a fair amount of damage. Aggron's typing makes it a great stop to common Pokemon like Ribombee and Galarian Articuno and grants a Toxic immunity, setting itself apart from other defensive Pokemon with Stealth Rock such as Regirock and Gigalith. However, its typing can hinder it against common Pokemon such as Gallade and Sandaconda. No reliable recovery makes defensive sets vulnerable to being worn down as well.