"Does this look like the Philadelphia Orchestra to you?" conductor Rossen Milanov, who looked an awful lot like a vampire, asked yesterday morning's Verizon Hall audience.

It didn't look like the traditional orchestra audience, either, but beneath the Death Eater masks and princess crowns were the usual faces of some culturally fortunate 4- to 12-year-olds and their parents and grandparents.

The ensemble's first family concert of the season fell on Halloween, so the orchestra seized the chance to alter the format. The audience got its lesson in how an orchestra works and sounds, but the repertoire turned ghoulish.

The event started with a costume parade at the Kimmel Center, the site of an outcropping of haunted outhouses and skeletons passing the time on benches.

Then the orchestra reprised a bit of an old Halloween concert tradition. For about a decade ending in 2005, the orchestra and audience got dressed up to hear Garrison Keillor or Tippi Hedren read Edgar Allan Poe's "The Raven" and watch clips from horror flicks. A drag queen hosted these events for a while, and orchestra members and staff would dress as Joan Crawford, a figure from Polish history, or the stray Playboy Bunny. The aim was to attract a hip, younger crowd to the orchestra.

For this even younger crowd, the orchestra cleaned up its act a bit. Not all members dressed up, but instrumental sections were populated with generic nerds (violinist Richard Amoroso), Little Red Riding Hood (violinist Dara Morales), and a nun, and in the back, tubaist Carol Jantsch dressed as an alarming large, yellow chicken.

Death came in musical form. Milanov's cartoonishly large ears shook as he led the orchestra through "Danse Macabre," which, he explained, was Saint-Saëns' portrait of dancing spirits. The harp plucked the 12 bells of midnight. The violin is historically the devil's instrument, and the musical interval of the tritone played by José Maria Blumenschein, concertmaster for the program, was the devil's calling card. The xylophone evoked dancing skeletons.

Richard Woodhams' oboe played the part of a rooster at daybreak, signaling that it was time for the spirits to make themselves scarce until next time.

The Sorcerer's Apprentice recalled the orchestra's history with the movie Fantasia, whose sound track spread fame for the ensemble and its music director at the time, Leopold Stokowski. And a new talent was introduced in Weber's Concertino in E Flat Major for clarinet and orchestra. David Kim, the impressive winner in the children's division of the venerable Albert M. Greenfield Competition, will always be able to look back on his 13th birthday as the day he made his Philadelphia Orchestra debut.

But it was a more contemporary sorcerer, in excerpts from the suite from Harry Potter and the Sorcerer's Stone, that seemed to have the biggest impact. The woodwind section was chosen to portray the Nimbus 2000, Milanov said, "because they are very agile and can make swift turns like the broom." The celesta solo, he said, had inspired a generation of children to take piano lessons. And if the young hands in the audience tracing air in three-quarter time were any indication, John Williams' score yesterday was having a magical afterlife, inhabiting the souls of some new conductors, too.