Marijuana one isnt, Harry J. Anslinger is the man that said that.

Indeed he did, BUT, that's not why marijuana was made illegal in 1920 - 1930.
That's equivalent to claiming "Armstrong was propelled to the moon by a metal bolt.."
While that's not entirely false, you're letting out a lot of other key factors.

Also, Harry J. Anslinger was a liar and a racist. I quote him:
“Reefer makes darkies think they’re as good as white men.”
“Marihuana leads to pacifism and communist brainwashing”
“You smoke a joint and you’re likely to kill your brother.”

So yea ..

Did he testify that he turned into a bat and flew around the room?

I am quite sure I've read that. Since I just checked it on Google. His name was Harry Anslinger.

Never mind, Harry is the guy that called the batman onto the stand to testify.