The WB network has yanked the much-anticipated season finale of "Buffy the Vampire Slayer," citing the recent shootings at high schools as the reason.

"Graduation Day, Part 2," which was scheduled to air tonight, will be replaced by an encore "Buffy" episode called "Band Candy," in which all the parents start acting like kids and the kids like parents. WB will air Part 2 of the season finale during the summer, and may package it with Part 1 as a two-hour movie, a network spokesman said.

"It is out of sympathy and compassion for the families and communities that have been devastated by the recent senseless acts of violence perpetrated on high school campuses that we have decided to delay this broadcast," said WB's chief executive, Jamie Kellner. "Our decision is also borne out of a deep sense of responsibility to the WB's loyal young audience," he added in a statement.

WB execs were concerned about the climactic scene of the season-wrapper. In it, the mayor is giving the commencement speech at Sunnydale High during a solar eclipse, which causes him to morph into a 60-foot serpent and attack the students. Buffy and her classmates defend themselves with Goth-type weapons.

Given the current climate, broadcasts depicting acts of violence--even against 60-foot serpents and vampires--at a graduation ceremony are inappropriate as high schools really are having their graduation ceremonies, Kellner said.

"We apologize to the millions of loyal 'Buffy' viewers who are eagerly anticipating this episode. We sincerely hope that you understand that the last thing we want to do is preempt our season finale. However, at this time, we feel that it is the best and most responsible decision for us to make," he added.

"Buffy" fans aren't the only ones who will be unhappy about the decision. This means a major blow to WB stations during the important May sweeps derby, when ratings are used to set ad rates for the coming months. The "Buffy" finale was likely to have been one of WB's highest-rated May shows.

Part 1 of the "Graduation Day" finale aired last week, leaving Buffy's vampire boyfriend Angel (David Boreanaz) barely clinging to life after being poisoned by an arrow from the bow of Slayer-gone-bad Faith, and the mayor preparing for his "ascension" into a total demon.

20th Century Fox TV, which produces "Buffy," took the high road yesterday.

"It should not go unsaid that the 'Buffy the Vampire Slayer' season finale was another remarkable hour for one of TV's most thoughtful and critically praised dramas that at any other time would have been recognized only as such," the studio said. "But in light of the terrible tragedies befalling our nation's high school campuses, we understand the WB's concerns over the timing of the episode and respect their decision to delay its airing."

The WB network is owned by Time Warner, which also owns the Warner Bros. studio. That studio was recently found at fault by a jury for the death of a guest on its "Jenny Jones Show." A Michigan jury awarded $25 million to the parents of a gay man, Scott Amedure, who was murdered by another guest on the show, Jonathan Schmitz, three days after Amedure revealed he had a crush on Schmitz, who said he was heterosexual. The jury agreed with the family's claim that the show so humiliated Schmitz that it drove him to commit murder. Time Warner plans to appeal.

The "Buffy" finale is just the latest program to be pulled in the wake of the massacre at Littleton's Columbine High School, which left 15 dead. WB axed an earlier episode of "Buffy" in which she discovered that a classmate was plotting mass killings at the school; CBS nixed an episode of "Promised Land" about a shooting at a high school in Denver, where the show is set. In Denver, the ABC station also axed that network's movie "Mr. Murder," while the NBC station pulled that network's "Atomic Train" miniseries, about a train with a nuclear bomb aboard that blows up Denver.

NBC execs aren't worried that the other broadcast networks are taking on their Thursday lineup next fall--because they're all doing it.

"It would be one thing if one network came after us, but you have five networks counterprogramming against each other, which is the real story," says NBC West Coast President Scott Sassa.

ABC, CBS, Fox, WB and UPN all detailed aggressive pushes into Thursday night when they unveiled their schedules to advertisers last week. For years, they've conceded Thursday to NBC. But NBC took a hit on the night this season with the loss of "Seinfeld" and George Clooney's departure from "ER," and the other networks smelled blood when Fox managed to siphon portions of Thursday's young male viewers with cheap "reality" specials. ABC, Fox, WB and UPN have slated teen-seeking shows in the night, including ABC's new drama series "Wasteland" from Kevin Williamson ("Scream"), Fox's animated "Family Guy" and UPN's "WWF Smackdown," while WB is moving its most successful new series, "Charmed," to 9 p.m. Thursdays.

And CBS, which has had luck for the past few seasons countering NBC's lineup with older-skewing fare, continues that strategy but has moved a revitalized "Chicago Hope" to 9 p.m.

NBC's new programming chief, Garth Ancier, thinks his network will finish next season in first place. At least he said so when his network's new prime-time schedule was presented to advertisers in New York last week. Yesterday, however, he was hesitant to repeat the forecast during a phone conference with reporters.

This season, which ends tomorrow night, NBC will finish first among the 18-49 demographic--the one that advertisers pay top dollars to reach--but will have lost its hold on total viewers to CBS.

But Ancier did assess the competition's schedules: ABC, NBC's main competitor, moved too many shows--a bad idea when the proliferation of channels already has caused so much viewer confusion, he said. Fox may drop some viewers this season because it's taken its reality shows off the air. And WB--where Ancier was programming chief until starting his NBC job two weeks ago--has too many versions of the same show.

" 'Safe Harbor' is really another '7th Heaven'; 'Angel' is another version of 'Buffy,' " and the new drama "Popular," about the travails of high school life, is like a lot of other WB shows, Ancier complained.

Pulling "Homicide" was a tough decision--but the right one, he insisted. The choice was whether to whack the cast and start anew, or move ahead with a new show from Tom Fontana, and NBC chose the latter.

"Sometimes with an aging show you're better off taking it off . . . before the fall. Look at 'Mad About You.' I understand why it was picked up [last spring for this season], but I think everyone kind of regrets it now," he said. However, he acknowledged that his mom--a "Homicide" fan--gave him a lot of grief about NBC's decision.

CAPTION: No diplomas yet for Sarah Michelle Gellar and David Boreanaz.