A two-headed mermaid with glittery horns led the pack, with a headless, hot-pink torso in a teal bikini close behind. The whimsical creations snaked along the Potomac River yesterday, turning heads from Gravelly Point to the Key Bridge.

The floating procession--which also included a phoenix with 14-foot shimmery wings and a geometric creation that one onlooker described as a "square baseball"--was a trial run for what some local artists hope will become an annual event to draw attention to the waterfront.

The "Mysteriously Curious Guerrilla Flotilla," as it was called, was conceived by Alexandria artist Justine Scherer and came to fruition with the help of the Arlington County Department of Parks, Recreation and Community Resources. The four artist-designed floats, part of a public arts festival at Gateway Park in Rosslyn, moored for the afternoon at Theodore Roosevelt Island.

The county plans to launch a second flotilla in May as part of a spring arts event and to include as many as 50 floats. "Our thought is that we could make this into an attraction that will bring people to Washington," said John Palmer Claridge, Arlington County's director of arts programming.

Yesterday, success meant simply getting the four pontoons into the water and gauging how well the sculptures--made of chicken wire, cardboard, lampshades and other odds and ends--would handle the wind and the current.

Daryl Dean, a 6-year-old District boy who came to Gravelly Point to fly his kite and watch planes land at National Airport, leaned over the edge of the pier to watch as the artists prepared to begin their voyage.

"What is this, a parade in the water?" Daryl asked. "I've never seen a parade in the water. It's cool."

By the water's edge, John Benoit and Donny Lee gently eased a large white sphere with painted black ribbons into the river. Benoit, who designed the creation, envisioned that the large ball, and a smaller one, would bob behind a massive white cube.

Although he had experimented in his bathtub with small models, Benoit was a little worried that the larger ball, covered with papier-mache, might sink. "Let it down," Benoit said nervously, watching as the sphere hit the murky water and bobbed up. "It's going to work, dude. It's going to float."

Scherer, who works as a costume designer, said she decided to organize the flotilla after some friends in Chicago created floating sculptures for fun. The name, she said, came about when different friends added words onto "flotilla."

Apart from a few snags, including a little trouble steering the pontoons with a single boat, the artists deemed the test a success.

"We made it," Lee said as the pontoons moored shortly before 2 p.m. "But more importantly, the art made it."