Was that a cow? And what about the man with the green ballons bobbing off his head -- or that little silver robot that kept running into people's knees?

It was that kind of night -- full of strange apparitions and spontaneous one-liners at the Beaux Arts Masquerade party at the Corcoran Gallery of Art, given last night by the Corcoran School.

Don Ellison, an astrophysicist at the Goddard Space Flight Center, towered several feet over a young woman. "Do you find tall men irresistible?" the asked, cloaked in blue satin robe and silver hat.

Carmen Kreeger, wife of David Lloyd Kreeger, a trustee of the Corcoran, walked up to Ellison, grabbed his robe and pulled it open to reveal wooden blocks tied to his feet. "Will you return the favor?" Ellison asked Carmen Kreeger, and she whipped back her dress to reveal long pants.

David Lloyd Kreeger was not in custome. "I'll tell you why," he said. "Last time I went to a masquerade party I won a prize for the funniest mask -- and I wasn't even playing."

Peggy Cooper, chair of the D.C. Commission on the Arts and Humanities, appeared as "Chiquita Escuela," in a Pittsburgh Pirates jersey, baseball cap and knickers.

Cooper had just returned from one of the dinner parties that had been given before the custome party. "This man asked me to take his coat at the Sulgrave Club," said Cooper grinning. "He thought I was the coat boy.

And he was a friend of mine. He couldn't believe it was me."

Chris Mittendorf, owner of the Midendorf-Lane gallery, showed up in a gray flannel suit. "I am in custome," he said looking down at his red jogging shoes. "I'm Michael Douglas."

The Coneheads stood by chatting. "I wanted to be a Conehead for a long time," said energy economist Howard McClintic. "My colleagues are all coneheads."

It was the second annual fund-raising party for the Corcoran School, and there will probably be more, turning out such spectacles as the lizard, who slinked by in a grotesquely bumpy green head, a creation of papier mache and modeling paper, airbrushed with enamel -- "I started this two months ago for Halloween," said Lizard artist Mark A. Behme, "and I didn't finish it in time. But I found out about this."