The Big M commercial on The Ed Sullivan Show

[snopes]

Comment: I remember back in the late 50's on The Ed Sullivan Show that a new
Mercury "Big M" was entombed, buried or otherwise hidden away for
retrieval at a later date. I think the year was 1957 or 1958. Mercury
was the show's sponsor. A big production was made of the event, with Ed
going back and forth to the location of the entombment via "live"
cameras. The ceremony surrounding the event was similar to the red
carpet awards shows.

Anyone remember it?