Line 1 large baking sheet - and 2 smaller baking sheets - with parchment paper, scatter sesame seeds over each.
Once dough has doubled, punch it down, and divide it out into 2 equal sized pieces.
On the large prepared baking sheet, form one round into the body of the spider. I like to do a round / dome / boule shape, but you can elongate it if you want to go for accuracy.
Take about ⅕ of the remaining half of the dough, and form another ball shape for the head. Wrap the ⅘ remaining dough in plastic, set aside.
Place the head next to the body - touching it, but just barely. You want to leave some room for expansion.
Cover loosely with plastic wrap and allow to rise for another 45 minutes or so.
Once time is up, preheat oven to 350 F, remove plastic wrap from the body/head loaf.
Whisk egg together with 1 tablespoon of water, gently brush over the tops and sides of the head and body.
Generously scatter black sesame seeds over the whole loaf.
You can attach olive slices for eyes at this point, or you can add them after it’s baked. If adding them now, I like to secure them with toothpicks - you can remove them after they bake.
Bake body for 35-40 minutes.
As soon as the body is in the oven, divide remaining dough into 8 equal sized pieces.
Roll each dough piece into a ~ 12” long rope.
Place dough ropes onto the 2 smaller baking sheets, forming each into an angular “leg”, as shown.
Cover with plastic wrap and allow to rise for another 30 minutes, as the body bakes.
Once the body is done, brush the legs with egg wash, sprinkle with sesame seeds.
Bake legs for 15-18 minutes.
Allow all pieces to cool before assembling. If you’re making this ahead of time, store all pieces in an airtight container until ready to use.