Labrador syndrome
When someone can't stop barking at nothing and forgets what they were doing. Like a dog that gets distracted by a leaf and forgets it was chasing a squirrel.
I was trying to finish my math homework, and then I saw a bug on my desk and forgot about everything.
She was in the middle of a big presentation when she saw a pigeon outside the window and started laughing like a maniac.
He was about to text his crush when his dog ran in and started chasing a sock.