David Harbour cannot say this 1 simple word in hilarious 'Stranger Things' blooper

David Harbour is an accomplished, professional actor with 17 years' experience in the business.

But that doesn't mean he can make it through a scene where he's required to say the word "grandma" without totally cracking up.

To celebrate hitting the 500,000 follower mark on Twitter, the official Stranger Things writers' account shared a clip that they described as "the Duffers' favorite bloop from s3."

Without spoiling anything, it's from the scene in which Hopper tries to get rid of Mike, who he's worried is spending too much time with Eleven.

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Can we take a minute to appreciate Finn Wolfhard saying "you got this" and Milly Bobby Brown breaking character to ask Harbour what's wrong with him?

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Oh, to spend just a minute on the Stranger Things film set.