Which pest is known to produce a foul odor and stain curtains?

The boxelder bug is recognized for its tendency to produce a foul odor and can leave stains on materials such as curtains. This odor is often released as a defense mechanism when the bug feels threatened. Additionally, the boxelder bug feeds on the sap of boxelder trees and may inadvertently stain surfaces with its excrement, which contains plant material and can leave noticeable marks. This characteristic makes it important to identify and manage this pest effectively to prevent damage to household items and maintain a clean environment. The other pests listed do not have the same combination of odor and staining capabilities, making boxelder bugs distinct in this regard.