We present the first detection of 24 µm variability in 24 sources in the Local Group galaxy M33 . These results are based on 4 epochs of MIPS observations , which are irregularly spaced over \sim 750 days . We find that these sources are constrained exclusively to the Holmberg radius of the galaxy , which increases their chances of being members of M33 . We have constructed spectral energy distributions ( SEDs ) ranging from the optical to the sub-mm to investigate the nature of these objects . We find that 23 of our objects are most likely heavily self-obscured , evolved stars ; while the remaining source is the Giant HII region , NGC 604 . We believe that the observed variability is the intrinsic variability of the central star reprocessed through their circumstellar dust shells . Radiative transfer modeling was carried out to determine their likely chemical composition , luminosity , and dust production rate ( DPR ) . As a sample , our modeling has determined an average luminosity of ( 3.8 \pm 0.9 ) \times 10 ^ { 4 } L _ { \odot } and a total DPR of ( 2.3 \pm 0.1 ) \times 10 ^ { -5 } M _ { \odot } yr ^ { -1 } . Most of the sources , given the high DPRs and short wavelength obscuration , are likely ÒextremeÓ AGB ( XAGB ) stars . Five of the sources are found to have luminosities above the classical AGB limit ( M _ { bol } < –7.1 mag , L > 54,000 L _ { \odot } ) , which classifies them as probably red supergiants ( RSGs ) . Almost all of the sources are classified as oxygen rich . As also seen in the LMC , a significant fraction of the dust in M33 is produced by a handful of XAGB and RSG stars .