This recipe for octopus affogati is from Sal Scognamillo of Patsy's Italian Restaurant.
Bring a large pot of water to a boil over high heat. Add octopus and cook for 1 hour; drain, reserving 1/2 cup cooking water.
In a medium saucepan, heat olive oil over medium heat. Add garlic and cook until browned, 2 to 3 minutes. Add octopus to skillet, along with marinara sauce, basil, and reserves cooking water. Cover and bring to a boil; let cook until thickened, about 20 minutes. Season with salt and pepper; serve immediately over linguine.