JSFiddle - React, Tailwind, and code Playground

HTML

<div class="objekt">
    Objekt
    <div class="hidden" id="hidden_items_found_18">
        0:3:0:0:0:0:2:0:0:- 0:0:0
    </div> 
</div>

CSS

.objekt{
    border: 5px red solid;
    line-height: 3em;
    height: 3em;
    width: 5em;
    padding: .3em;
    text-align: center;
    position: relative;
    
}
.hidden{
    opacity: 0;
    position: absolute;
    border: 5px red solid;
    top:0;
    left:0;
    background: #eee;
}
.hidden:hover{
    opacity: 1;
}