.style {
    display:inline-block;
    border:0;
    position: relative;
    transition: all 200ms ease-in;
    transform: scale(1);

}

.style:hover {
    z-index: 2;
    transition: all 200ms ease-in;
    transform: scale(1.5);
}


<div class="style">
                        <a href="https://giphy.com/gifs/killua-qDO6QPt4VczVS" target="_blank">
                        <img src="Source_Files/Killua.gif"></a>
                    </div>