The only way to get rid of that blanket forever is to do something drastic, something that stupid dog can't do anything about.
8 seconds sound clip from the It's an Adventure, Charlie Brown movie soundboard.
You can hear this line at 00:43:01.341 in the Blu-ray version of the movie.
Quote context
[...]
- I've got to find it. I've got to find it. I've got to dig everywhere until I find that blanket.
- My blanket! Snoopy, you found it. You found it. You found my blanket.
- I hear Linus got his blanket back.
- Stupid dog. Well, it's obvious.
- Do you mean to tell me that's my blanket flying around out there?
- How could you do such a thing?
- Oh, no!
- Ah!
- You didn't mean to? A lot of good that does.
[...]