MOSCOW - A three-eyed alien with a robot sidekick landed aboard a spaceship and made a boy vanish by zapping him with a pistol, a Soviet newspaper reported Tuesday in a second day of strange tales in the state-run media.

But as the bizarre saga of the space invasion of the city of Voronezh unfolded for a second day, a scientist whose words were used to buttress the first published report voiced doubts and said he was in part misquoted.

''Don't believe all you hear from Tass,'' Genrikh Silanov, head of the Voronezh Geophysical Laboratory, said from Voronezh in a telephone interview with The Associated Press. ''We never gave them part of what they published.''

On Monday, the usually staid, official Soviet news agency told the world that scientists had confirmed that an alien spaceship carrying giant people with tiny heads had touched down in Voronezh, a city of more than 800,000 people about 300 miles southeast of Moscow.

As many as three aliens 13 feet tall left the spacecraft, described as a large shining ball, and walked in the park with a small robot, Tass reported. A Tass duty officer stood by the story. ''It is not April Fools' today,'' he said.

The purported close encounter in Voronezh was only the latest weird tale to appear in the Soviet media. Under the policy of glasnost, or openness, the media have recently told of other sightings of unidentified flying objects and the yeti, or Abominable Snowman.

Monday's report spawned rumors in Moscow, including one that the aliens told Voronezh residents the Earth would be destroyed by the year 2000 if people didn't stop polluting it.

Nonetheless, a Communist Party paper whose avowed mission is to write about culture was the only major national daily to print anything Tuesday about the UFO, indicating that more authoritative newspapers like Pravda had thought the topic too hot to handle.

Sovietskaya Kultura said its coverage had been motivated by ''the golden rule of journalism: The reader must know everything.''

The daily quoted witnesses as saying that the UFO flew into Voronezh on Sept 27. At 6:30 p.m., it said, boys playing soccer saw a pink glow in the sky, then saw a deep red ball about 10 yards in diameter. The ball circled, vanished, then reappeared minutes later and hovered, it said.

A crowd rushed to the site, Sovietskaya Kultura said, and through an open hatch saw a ''three-eyed alien'' about 10 feet tall, clad in silvery overalls and bronze-colored boots and wearing a disk on his chest.

The newspaper, quoting witnesses, gave this account:

The UFO landed. Two creatures, one apparently a robot, exited. A boy screamed with fear, but when the alien gazed at him, with eyes shining, he fell silent, unable to move. Onlookers screamed, and the UFO and the creatures disappeared.

About five minutes later, they reappeared. The alien had a ''pistol'' - a tube about 20 inches long, which it pointed at an unidentified 16-year-old boy, making him disappear. The alien went inside the sphere, which took off. At the same time, the boy reappeared.

''Children and eyewitnesses of the abnormal phenomenon have been questioned by police workers and journalists,'' wrote E. Efremov, the Voronezh correspondent for Sovietskaya Kultura. ''There are no discrepancies in the description of the sphere itself or the actions of the 'aliens.' Moreover,
all the children who became witnesses to this event are still afraid, even now.''

It gave the names of only three witnesses, all youngsters.

Scientists from a nationwide group that investigates ''abnormal phenomena'' were looking into the landing, the newspaper said.