In order to slide the background color up you would need to use a background image, or a gradient of some sort, while gradually adjusting the background-position
:
.box {
width: 200px; height: 100px;
background-size: 100% 200%;
background-image: linear-gradient(to bottom, red 50%, black 50%);
-webkit-transition: background-position 1s;
-moz-transition: background-position 1s;
transition: background-position 1s;
}
.box:hover {
background-position: 0 -100%;
}
<div class="box"></div>