Look at each slice and find the flattest edge. That edge becomes the top of Frankenstein's head. Lay the bread on the nori and mark where the hair should end so you can cut it to size.
Put the slices in the toaster and toast them to your liking. I go a little darker than usual because the avocado softens the bread. A crisp base keeps the face from turning soggy.
While the bread toasts, cut the nori into hair, a mouth, and a nose. Make the hair with a flat top and pointed triangles along the bottom. For the mouth, cut one long strip and a few short strips to make the stitches.
Cut the black olive into short rounds so each slice has a hole in the middle. You need about four rounds for two toasts. If you skip the olive, small nori triangles also work as eyes.
Scoop the avocado into a small bowl and mash it with a fork. Add the salt and a squeeze of lemon or lime juice. Mash until it feels creamy but still holds a little texture.
When the toast is ready, spread a generous layer of avocado over each slice. Go all the way to the edges so the green face looks full. Turn the toast so the flat edge sits at the top.
Lay the nori hair along the flat top edge first. Add the nose, then place the olive rounds for eyes. Finish with the long mouth strip and press the short strips across it to make the stitches.
Set the toast on a board or plate and enjoy it while the bread is still crisp. The nori softens after a while, so I eat mine within a few minutes. Take a quick photo first, because it looks great.