just can't make clearInterval() works

Question

I've read through all post related to clearInterval, but somehow just can't make it work... What the script does is the interval will be set once the ".xmas-title" change the image. And the interval will be cleared once the mouse click.

var animation;
$(".xmas-title").delay(4000).fadeIn(400, function(){
    bear_shake(true);
});

$(".xmas-more").delay(4200).fadeIn(400, function(){
    $('.bg-xmas').css( 'cursor', 'pointer' );
    $(".bg-xmas").click(function(){
        show_msg();
        bear_shake(false);
    });
});

function bear_shake(bool){
    if(bool){
        animation = setInterval(function(){
            $(".xmas-bear").delay(200).fadeOut(0, function(){
                $(".xmas-bear").children("img").attr('src', 'images/xmas/xmas-bear_o1.png');
            }).fadeIn(0);
            $(".xmas-bear").delay(200).fadeOut(0, function(){
                $(".xmas-bear").children("img").attr('src', 'images/xmas/xmas-bear_o2.png');
            }).fadeIn(0);
        },0);
        console.log('true');
    }else{
        clearInterval(animation);
        console.log('false');
        $(".xmas-bear").children("img").attr('src', 'images/xmas/xmas-bear.png');
    }
}

Answer 1

Thank you guys, it seems I miss the basic thing and just tried to make things difficult on my own. I've combine all you guys' opinions, and get it works now. function bear_shake rewrite as below:

function bear_shake(bool){
    if(bool){
        var i = 2;
        animation = setInterval(function(){
            if(i % 2== 0){
                $(".xmas-bear").children("img").attr('src', 'images/xmas/xmas-bear_o1.png');
            }else{
                $(".xmas-bear").children("img").attr('src', 'images/xmas/xmas-bear_o2.png');
            }
            i++;
        },200);
    }else{
        clearInterval(animation);
        $(".xmas-bear").children("img").attr('src', 'images/xmas/xmas-bear.png');
    }
}

it now looks clear and simple for me, thank you all. and I'm wondering is there any other better or smarter way to do this?