Is it illegal to carry an expandable/extendable baton in the state of Indiana?
Indiana has no state law against carrying an expandable baton, a.k.a. asp. (Hard to prove a negative, but here's one reference in support.) NB: Batons are considered deadly weapons.
NBB: Laws on these weapons vary tremendously by state, and sometimes even by city, so this answer should not be construed to apply to any jurisdiction outside of Indiana!