Apparently this plugin was forced in with the latest WordPress update. The problem is you might not know you even have it!
I just went though two weeks of having my site go down over and over, 502 and 503 errors, EXTREMELY slow loading, even the admin side was not working...
I've made over a dozen WordPress sites and I know the routine... I went through every plugin over and over, checked the theme, and fought with GoDaddy on three different days thinking it HAD to be their server.... Today, I happened to notice something I had never seen before. In addition to installed plugins, and the Must Use plugins, I saw an option for "Drop-in" plugins. What the hell is that? Lo and behold, I find something called "object-cache.php APCu Object Cache"
You have to FTP in to your site and delete it from the main directory in order to get rid of it. My site was perfectly FINE once I removed it. What a massive, ridiculous hassle - for WordPress to give me this hidden plugin without my knowing.
(I suggest you download a copy of object-cache.php before you delete it, in case you want to put it back... you never know...)