Put 3 tablespoons of butter in a medium skillet over medium heat. Core, seed, and chop the pepper; add it to the skillet.
Cook the pepper, stirring once or twice until it begins to soften, 2 or 3 minutes.
Add 1 1/2 cups corn and 1 cup lima beans and sprinkle with salt and pepper. Cook, stirring occasionally until both are hot all the way through, 3 to 4 minutes.
When the succotash is hot, taste and adjust seasoning and serve hot or at room temperature.