Many social media users mocked former special counsel Robert Mueller for his testimony in front of the House Judiciary Committee on Wednesday morning, including first son Donald Trump Jr.

Mueller testified in front of the committee about his two-year long investigation concluding that the president’s campaign did not conspire with Russia to win the 2016 presidential election.

The second half of his 448-page report details multiple instances in which Trump may have committed obstruction of justice, but he did not come to a decision on those cases due to a Department of Justice guideline against indicting a sitting president.

The ex-special counsel’s testimony, however, was mired by him stumbling, appearing unfamiliar with the report, and with him asking for members of the committee to repeat himself.

A number of social media users mocked him for those instances as did the Drudge Report, which wrote, “DAZED AND CONFUSED” at the top of their site with a link to a montage of Mueller’s stumbling.

Don Jr. retweeted conspiracy theorist Dinesh D’Souza who suggested Mueller was mentally retarded.

Does anyone honestly believe that after two years and $50 million Robert Mueller does not know anything about fusion GPS given that it was the genesis of the entire investigation?

Has he not opened a paper, even a leftist, one or watched TV in that time?

Tough to believe. https://t.co/x25WxGNY3j

— Donald Trump Jr. (@DonaldJTrumpJr) July 24, 2019

Others also jumped in to poke fun at Mueller:

INBOX: pic.twitter.com/x5S7h4JLB2

— Comfortably Smug (@ComfortablySmug) July 24, 2019

either Mueller is senile or he is lying. Over and over again he could not remember even the most basic facts of his report. And yet if there was a question which attacked the president with regards to the report he had perfect recollection.

— Bill Mitchell (@mitchellvii) July 24, 2019

Merely an observation: Mueller looks like a tired old man who is confused, unable to stay up with questioning and potentially suffering early onset of dementia. Like he’s there but clearly struggling in a real way.

— Ned Ryun (@nedryun) July 24, 2019

Mueller appears rambling, somewhat senile, not alert. Not the impressive figure I thought he would be. Superman loses his cape. Raises question: Was Weissman running things all along?

— Dick Morris (@DickMorrisTweet) July 24, 2019