Aaron Sims, who did visual effects for the show, told Screen Crush that Barb's original death scene was far more graphic — and he shared the concept art to prove it. In it, she's covered in cobwebs with her ribs jutting upward from her body and her insides spilling out.
"Based on our original discussion with the Duffers on this design, we wanted to go really graphic with it to highlight the horrific aspects of Barb being eaten, and something then growing on top of her," he explained. "Thus, the ribs poking out of her stomach in the first shot."
At the end, though, the logistics of portraying the death won out. “It was difficult to tell exactly what had happened to her; it wasn’t an issue of it being too graphic, but rather, that the viewer needed to see something that was very recognizably dead,” Sims said.
There's one way in which the final product was actually a bit grosser than the concept art. She's got a spider crawling out of her mouth here, but on the show, she had a slug.
Original Concept Art for @StrangerThings ... Barb's demise The beauty of working with the show creators #DufferBros, allowing us to go 'dark & disgusting' with scenes from the #upsidedown #weareallbarb #strangerthings #digitalart #zbrush #conceptart #netflix #barb2.0 #demogorgon #disgusting #decay #digitalpaint @aaronsimscreative