What's the name of this advertising technique???

Question

What's the name of the advertising technique, where there's loads of advertising done without like actually saying what it is.

For example, a new media company opened up, and their mascot was a cow. Suddenly, loads of plastic cows appeared everywhere - on the exteriors of vehicles, on posters, in the newspapers etc, and no one knew what it was for. So it aroused public interest. Then the media company announced it's set up.

Answer 1

It's called  "Guerilla marketing"

Answer 2

Undercover Marketing?