Topic: "Google.ads.doubleclick"

When working my computer I saw a box ( more as a sliding rule ) where a link slide extremely fast, showing among many characters:  "google.ads.doubleclick".
It runs so fast that I had no time to take any action.
I am under heavy suspicion that it means that I was tracked all the way, and could not do anything.
Does this happen with anyone ?
If so, how to delete such action ?
Please advise your experience with similar fact.
Rgds
Ostwald