Omastar

Omastar sports an unfortunate weakness to Ground in a metagame with numerous strong Ground-types and lacks the key resistance to Water that other bulky Water-types have. However, what sets it apart is its resistance to Normal and Flying. Granbull is an incredibly powerful threat in GSC UU, and Omastar is the best counter to it by far. Omastar's STAB Surf, solid coverage, and high Special Attack allow it to put a solid dent in almost any foe, an advantage it has over competing Normal-resistant Pokemon such as Magneton, which struggles to hit Ground- and Electric-types hard. However, outside of countering Granbull and Dodrio and checking Scyther without Hidden Power Ground, Omastar's favorable matchups are few and far between, so it can sometimes feel like dead weight if the opponent chooses not to bring them.