p {
    position: relative;
    background-color: blue;
}

p:before {
    content: '';
    position: absolute;
    left:100%;
    width: 10px;
    height: 100%;
    background-color: red;
}

    
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I would like to trigger a click event only on the pseudo-element (the red bit). That is, I don't want the click event to be triggered on the blue bit.