"Don't Open Till Doomsday" is an episode of the original The Outer Limits television show.
"In 1929, a pair of young newlyweds receives a mysterious box-like object wrapped as a wedding gift with a cryptic label reading "Don't Open Till Doomsday".
Unbeknownst to his bride, the bridegroom is zapped by a beam of light emanating from this object when he removed it from the wrapping, and seemingly disappears out of existence.
Thirty-five years later, in 1964, an eloping couple arrives at the house in the hopes of using it as a honeymoon spot, now a half-derelict mansion owned by Mrs. Kry, an eccentric old woman who turns out to be the aforesaid bride, driven to insanity after her husband disappeared.
Facing refusal, and being further hindered by an angered Mrs. Kry, along with the father's false promise to aid in the search if freed from captivity, the enraged alien resorts to self-destruction after setting the daughter free, thus 'uncreating' himself, and obliterating the entire mansion, the father, Mrs. Kry and her bridegroom in the process, with the young couple narrowly escaping the carnage.