JSFiddle - React, Tailwind, and code Playground

HTML

<script src="https://cdnjs.cloudflare.com/ajax/libs/jquery/1.12.4/jquery.min.js"></script>
<div class="bottom_left_spider">
  <img src="https://s17.postimg.org/cc243pkrz/spiderweb.png">
  <div class="webscroll">
    <img src="https://s21.postimg.org/tbdww9hzr/spidy.png" class="spidy">
  </div>
</div>

CSS

body{background-color:#000}
.bottom_left_spider{position:absolute;width:180px;height:200px;left:0;top:0;z-index:998}
.webscroll{height:200px;width:1px;border-right:2px solid #2e2e2e;position:absolute;top:0;left:101px;z-index:9999}
.spidy{position:absolute;bottom:-51px;left:-29px}

JavaScript

$(window).scroll(function() {
    var bh = 0;
    var height = $(window).scrollTop();
    var sch = bh + height;
    
    $('.webscroll').stop().animate({'height': sch}, 400)
    if(height <= 19) {
        $('.webscroll').stop().animate({'height': 200}, 600)
    }
});