jQuery constructor de objetos dobles - por ejemplo, $($(this))

Suponga que tiene el siguiente código:

function name() {
    $(this).css('background', 'red');
}

$('selector1').click(name);

$('selector2').click(function () {
    name.call($(this).parent());
});

Now, when the function is called by clicking on 'selector1' this is an HTML object and $(this) a jQuery object, but if the function is called by clicking on 'selector2' this is already a jQuery object so what is $(this)?

Sé que podría hacer algo como name.call($(this).parent()[0]); to get an HTML object, but my question is what happens when you do something like $($(this)) or $($('selector'))? What is the result of that and, most impotently, is there any harm in using such a construct?