Look! In the sky! It's a bird, it's a plane. No. It's Superman. No, it's not, it's Sen. John Tower.

A small portion of the planet Krypton fell to earth Saturday night and landed in Dallas, when a mixture of the Dallas press and the state's leading politicians got together for a gala Superman costume party, starring the 5-foot-6-inch Republican senator as the Man of Steel.

The 500 invitation-only guests filled the ballroom at the posh Northpark Inn shopping center complex in north Dallas. Republican Gov. Bill Clements had a walk-on part as "The Man in the Phone Booth."

"I was born to play Superman," said Tower, dressed in the appropriate blue tights and top and red satin cape and obviously relishing the role.

Some Texans call the annual event the best party in the state. Five years ago Joe Barta, who handles the shopping center's public relations, and his friend from high school days, Buddy Beck, began giving theme parties as a joke. The events were so popular that they have become more elaborate each year. Barta was once a reporter, and his wife Carolyn is political editor of The Dallas Morning News. Beck does PR for Atlantic-Richfield.

It's been a tradition since the beginning for Tower to appear in a skit built around the theme of the party, and in the past he has been a disc jockey and a cowpoke. In the "Casablanca" skit, Tower played the role of Ugarte that Peter Lorre made famous in the movie.

"We just have a lot of fun," said Barta.

In Saturday night's skit, Tower's job as Superman was to rescue an innocent woman and try to convince a wicked vixen to mend her ways, all of which he managed to do with a great deal of leaping and strutting on stage and a flinging about of his cape.

In one instance, Tower was about to go into his phone booth to make his dramatic change when he opened it and discovered Gov. Clements.

Clements, who stopped off in Dallas on his way to the National Governors Conference in Washington, said it was a party he wouldn't dare miss. "Now when would I have a chance to mess around with Superman."

Freshman Rep. Martin Frost also had a leading role. A Democrat and the only Jewish member of Congress from Texas, he played a priest who gave the last rites to the damsel Superman rescued.

"I've always wanted to play a man of the cloth," said Frost.

Invitations to the party are prized, and this year, in keeping with the authenticity of the event, they were Daily Planet press cards. Some persons refused to give them up as they entered the enormous ballroom.

Those invited were told to come as their favorite comic-book character, and the crowd was a mixture of Supermen, Wonder Women and mild-mannered Clark Kents.

At the first party five years ago, Tower made his debut as a country-western singer and sang a song that has become his unofficial campaign theme song, Gene Autry's "I'm Back in the Saddle Again."

"Tower likes that part of the song about where a 'friend is a friend,'" explained one of his aides.

The reason the senator continues to take time out for the party, which included an afternoon rehearsal, said the aide, is because he's really "a latent actor."

"Being in the show reminds Tower of his early days when he was a radio disc jockey in Taylor, Tex., where he was known as Tex Tower," the aide said.

The evening clearly belonged to Tower. He drew the biggest applause as he tore down doors and dashed about in true Superman fashion.

Tower also had the best lines. "I'm a man who stands for truth, justice and the American way... always have and always will," he told the audience.

"But for right now, it's up, up and away," he said, and the audience cheered. CAPTION:

Picture, Sen. John Tower, by David Woo for The Washington Post