A glimpse of the Southern Jellyfish Nebula and its massive YSOEPMercerauthorMJWolffauthorTMBaniaauthorRABenjaminauthorMCohenauthorJMDickeyauthorJMJacksonauthorHAKobulnickyauthorJSMathisauthorSRStolovyauthorBUzpenauthorDPClemensauthorEBChurchwellauthorJMRathborneauthorMRMeadeauthorBLBablerauthorRIndebetouwauthorBAWhitneyauthorCWatsonauthorMGWolfireauthorIn Spitzer/IRAC images obtained under the GLIMPSE Legacy Survey, we have identified a unique and provocative nebular object we call the ‘‘Southern Jellyfish Nebula.’’ The Southern Jellyfish Nebula is characterized by a fan of narrow tendrils with extreme length-to-width ratios that emanate from the vicinity of a bright infrared point source embedded in a smaller resolved nebula. From CO observations of the Nebula’s morphologically associated molecular cloud, we have derived a kinematic distance of 5:7 0:8 kpc and a cloud mass of 3:2 0:9 ; 103 M. The tendril-like ropes of the Nebula have widths of 0.1 pc and lengths of up to 2 pc. We have integrated the infrared spectral energy distribution (SED) of the point source to establish it as a massive young stellar object (MYSO), most likely forming alone, but possibly masking fainter cluster members. The shape of the SED is consistent with the shape of a late Class 0 SED model. Based on its far-IR luminosity of 3:3 0:9 ; 104 L, the Southern Jellyfish’sMYSO has a zero-age main sequence (ZAMS) spectral type of B0. Given the curious nature of this nebula, we suspect its peculiar IR-bright structure is directly related to its current state of star formation.240101 Astronomy and Astrophysics2007University of Chicago PressArticle