Cook noodles: Boil noodles in salted water until al dente. Drain and toss with a small drizzle of oil to prevent sticking.
Prepare crustaceans: Pat dry shrimp, crab, or lobster chunks. Season lightly with salt and pepper.
Make garlic butter sauce: Melt butter in a large skillet over medium heat. Add garlic and sauté 1–2 minutes until fragrant. Avoid burning.
Cook seafood: Add crustaceans to the skillet. Sear shrimp 2–3 minutes per side until opaque; heat crab or lobster gently until warmed through.
Combine noodles and sauce: Toss cooked noodles with garlic butter, crustaceans, oyster sauce, soy sauce, and sugar. Mix well for even coating.
Finish & serve: Sprinkle sliced green onions on top, squeeze fresh lemon over the dish, and serve immediately.