In 1994, Alien concept designer HR Giger was asked to design a Batmobile for Batman Forever. His spindly, pincer-like design is an oddly organic take on Batman's tech, but still an improvement over the neon-lit monstrosity that was ultimately chosen.
Batmobile Art has a more detailed description of Giger's design:
His unique "X" shaped design was to include articulated front legs/mandibles, retractable fins, and gatling gun emplacements on each of the four pods on the sides of the vehicle. The design also combined side and forward intake ports with organinic spines and a central pod connecting the four legs.
H.R. Giger's Batmobile design [Super Punch]