  We present Spitzer Space Telescope observations of the "evolved starless
core" L1521F which reveal the presence of a very low luminosity object (L <
0.07 Lsun). The object, L1521F-IRS, is directly detected at mid-infrared
wavelengths (>5 micron) but only in scattered light at shorter infrared
wavelengths, showing a bipolar nebula oriented east-west which is probably
tracing an outflow cavity. The nebula strongly suggests that L1521F-IRS is
embedded in the L1521F core. Thus L1521F-IRS is similar to the recently
discovered L1014-IRS and the previously known IRAM 04191 in its substellar
luminosity and dense core environment. However these objects differ
significantly in their core density, core chemistry, and outflow properties,
and some may be destined to be brown dwarfs rather than stars.
