Can it be diesel fuel ? (should smell)
Or water dripping from a slight leak in the exhaust system ? (no smell)
I can not think of more transparent fluids?
Did you use the "defog" button on your AC, this will also create water.
Tranny oil will probably look almost transparent in small amounts.

Put a tray with clean water under and see if the dripping creates some oily film or pattern if you dont like to taste it as is...
L.