Toast the four slices of bread until they are golden and firm.
Cut each toasted slice into three small rectangles to create bite-sized pieces.
Mash the avocados in a bowl with the lemon juice and salt until mostly smooth.
Spread the mashed avocado evenly over the toast rectangles.
Cut thin strips from the nori sheet and place them across the top of each piece to form hair.
Slice the black olives and add two slices to each bite for eyes, plus one slice on each side for bolts.
Lay one red bell pepper strip below the eyes on each bite to create a mouth.