<div class="wrap">
  <div class="resizer"></div>

  <div class="x">✖</div>
</div>

.resizer {
  width: 100px;
  height: 100px;
  background: white;
  overflow: hidden;
  resize: both;
}

body {
  background: #ccc;
  margin: 0;
}

.wrap {
  width: min-content;
  position: relative;
}
.x {
  pointer-events: none;
  position: absolute;
  bottom: 0;
  right: -20px;
  line-height: 0;
  color: red;
  font-size: 50px;
}