Calvin, a mischievous 6-year-old with America's most vivid imagination, and his stuffed tiger Hobbes have finally met a monster even they cannot overcome: Their creator.

Bill Watterson, "father" of Calvin & Hobbes, has decided to move on after 10 years of chronicling the pair's countless snowball ambushes, treks through space and battles with dinosaurs, babysitters amd parents. The last strip will appear Dec. 31, ending its run as one of the wittiest and most popular in America.

"I believe I've done what I can do within the constraints of daily deadlines and small panels," the reclusive Mr. Watterson wrote in a letter sent to editors by Universal Press Sydicate, which distributes the strip to some 2,400 newspapers. "I am eager to work at a more thoughtful pace, with fewer artistic compromises."

For comic strip fans, it was another in a series of devastating blows.

Bad enough that Berke Breathed took Bloom County off the map six years ago and Gary Larson stopped taking us to the Far Side last January. But 1996 will be ushered in without Calvin & Hobbes. Mr. Watterson will send Calvin, his tiger and all their adventures into comic strip limbo.

"My heart is broken, I think it is a terrific strip," said Tim Kelly, editor of the Lexington Herald-Leader. "I don't know anything out there...that can replace it."

Mr. Watterson, who does not talk to reporters and assiduously shuns the spotlight, did not elaborate on his plans, other than to say he would continue his relationship with his syndicate.

But he doesn't appear likely to change his mind. "From my discussions with him, [I'd say] his decision is final," syndicate president John P. McMeel wrote in a letter accompanying Mr. Watterson's goodbye.

For fans of Calvin & Hobbes, many of whom anticipate each day's strip with near fanatical devotion, separation anxiety is already building.

"No! No! No! Don't tell me this," gasped Craig Hankin, sounding like a man who had just heard his dog had died. "Oh, no. He's going to stop doing the strip? My kids are going to be crestfallen. I'm crestfallen. Jeez, what a terrible thing to hear."

Mr. Hankin, who teaches drawing and painting at Johns Hopkins, wasn't so worried for himself -- he's an adult, after all, and can cope with loss. But he wondered how he would tell his two children, Joe, 11, and Charlie, 8.

"I'm going to have to get off the phone and break this to them very gently," he said, somewhat haltingly, "sort of like telling them the cat went up on the roof. I don't know what to say. I'm going to have to be very gentle about this."

Anne Wityk, who lives in Timonium with her husband and three young children, will also miss Calvin & Hobbes.

"It is one of my favorite comic strips," she said. "He does kind of keep doing the same jokes over and over, but they're good ones."

Like Bloom County and the Far Side, Calvin & Hobbes will depart the comics page with their best days seemingly ahead of them. Since debuting Nov. 18, 1985, the strip has consistently topped popularity surveys -- it's among The Sun's top five -- and has been collected in 14 anthologies, including the most recent, The Calvin & Hobbes' Tenth Anniversary Book.

Each of the first 13 books, all just collections of previously published material, sold more than a million copies. Besides reprints, the newest offers new strips and musings by Mr. Watterson.

In fact, Mr. Watterson has long been regarded as something of a maverick. He makes some $1 million annually off Calvin & Hobbes, but has turned down millions more by refusing to license the strip's characters.

"The world of a comic strip ought to be a special place with its own logic and life," he says in the Anniversary Book. I don't want some animation studio giving Hobbes an actor's voice, and I don't want some greeting card company using Calvin to wish people a happy anniversary."

Mr. Watterson's decision to quit does not come as a surprise to everyone. He took a nine-month leave of absence in 1991 and another leave last year. And in a 1989 speech at Ohio State University, he decried comic strips that overstay their welcome. Without naming names, he wondered aloud, "Why are some strips stumbling along decades after their creators have retired or died? Why do so many offer only the simplest interchangeable gags and puns? Why are some strips little more than advertisements for dolls and greeting cards?"

Mr. Watterson walked away before anyone could apply those same questions to him, said Roy Furchgott, a reporter for the trade-industry magazine Radio and Records.

"Good for him, he's leaving on a high note," Mr. Furchgott said. "He's not going to let this thing drag into oblivion, and that's fine."

Mr. Watterson's decision follows a sad pattern, said Mike Johnson, a clerk at Geppi's Comic World in Harborplace. His favorite strips: Calvin & Hobbes, Bloom County and the Far Side.

Copyright 1995 The Baltimore Sun.