Though fake seaweed is commonplace in aquarium and pet supply stores, try making your own for a costume party, parade float or other nautical-themed event. Create a mermaid or drowned sailor costume for Halloween using fake seaweed strands or make a sea-inspired display for a surf shop at the beach. Make less trash in the world by reusing plastic bags for your faux seaweed design. Refrain from placing homemade fake seaweed in fish tanks as the paint and plastic will injure -- if not kill -- your fish.
Cut 12-inch strips from plastic bags. Use a variety of plastic bags including those that are green and blue. Cut as many strips as you need for your project.
Twist the strips into thin, seaweed-like pieces. There is no right or wrong way to do this as seaweed comes in all shapes and sizes. Pull at some of the plastic on a few strips to create the webby look of some types of seaweed. Glue wooden or pony beads on other pieces to mimic the look of seaweed seed pods.
Paint the plastic as desired. Mix browns and greens together to create a brownish-green strain of seaweed. Paint any green and blue plastic strips with other blues and greens to create a varied effect as well as to paint over any wording that may still be obvious. Go over any beads with paint as well. Allow to dry.
Display your faux seaweed pieces as desired.
Look at images of various types of seaweed as inspiration for your fake seaweed craft.