Old E was definitely some nasty stuff. You could taste the charcoal filtering in every gulp. (Imagine pouring a cheap beer through a bag of Kingsford charcoal...you get the idea).
My nomination comes from my high school years. Malt Duck. It came in different flavors, (I clearly recall apple). Super sweet malt liquour. Nasty, nasty stuff. But it got you seriously zooted. (Late 70's term).

For those special times when the ladies were present, we would crack open some bottle of Champale. Once again, super sweet...

And if it was a really good nite, Riunite or Canei was purchased.

Just the thinking of the brain cells that I destroyed consuming this swill makes me want to hurl...