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The multiwavelength data of nuclear transient AT2018dyk, initially discoveredas a changing-look low-ionization nuclear emission-line region (LINER) galaxy,has been revisited by us and found being in agreement with a tidal disruptionevent (TDE) scenario. The optical light curve of AT2018dyk declines as apower-law form approximately with index -5/3 yet its X-ray emission lags behindthe optical peak by $\sim140$ days, both of which are typical characteristicsfor TDEs. The X-ray spectra are softer than normal active galactic nuclei(AGNs) although they show a slight trend of hardening. Interestingly, itsrising time scale belongs to the longest among TDEs while it is nicelyconsistent with the theoretical prediction from its relatively largesupermassive black hole (SMBH) mass ($\sim10^{7.38} M_{\odot}$). Moreover, aprominent infrared echo with peak luminosity$\sim7.4\times10^{42}~\text{erg}~\text{s}^{-1}$ has been also detected inAT2018dyk, implying an unusually dusty subparsec nuclear environment incontrast with other TDEs. In our sample, LINERs share similar covering factorswith AGNs, which indicates the existence of the dusty torus in these objects.Our work suggests that the nature of nuclear transients in LINERs needs to becarefully identified and their infrared echoes offer us a unique opportunityfor exploring the environment of SMBHs at low accretion rate, which has been sofar poorly explored but is crucial for understanding the SMBH activity.

AT2018dyk Revisited: a Tidal Disruption Event Candidate with Prominent Infrared Echo and Delayed X-ray Emission in a LINER Galaxy