  We use mid-infrared variability in galaxies to search for active galactic
nuclei (AGN) in the local universe. We use a sample of 10,220 galaxies from the
Mapping Nearby Galaxies at APO (MaNGA) survey, part of the Sloan Digital Sky
Survey (SDSS-IV). For each galaxy, we examine its mid-infrared variability in
the $W2$ $[4.6\mu m]$ band over thirteen years using data from the Wide
Infrared Survey Explorer (WISE) All-Sky and Near Earth Objects WISE (NEOWISE)
missions. We demonstrate that we can detect variability signatures as small as
about $7\%$ in the root-mean-square variation of $W2$ flux for the majority of
cases. Using other AGN signatures of the variable galaxies, such as optical
narrow lines, optical broad lines, and WISE $W1-W2$ colors, we show that $\sim
75\%$ of the variables show these additional AGN signatures, indicating that
the bulk of these cases are likely to be AGN. We also identify seven galaxies
that have light-curves characteristic of tidal disruption events. We present
here a publicly available catalog of the light-curve variability in $W2$ of
these galaxies.
