The Intermediate Palomar Transient Factory reported the discovery of an unusual type II-P supernova iPTF14hls .
Instead of a \sim 100-day plateau as observed for ordinary type II-P supernovae , the light curve of iPTF14hls has at least five distinct peaks , followed by a steep decline at \sim 1000 days since discovery .
Until 500 days since discovery , the effective temperature of iPTF14hls is roughly constant at 5000- 6000 \mathord { \thinspace K } .
In this paper we propose that iPTF14hls is likely powered by intermittent fallback accretion .
It is found that the light curve of iPTF14hls can be well fit by the usual t ^ { -5 / 3 } accretion law until \sim 1000 days post discovery when the light curve transitions to a steep decline .
To account for this steep decline , we suggest a power-law density profile for the late accreted material , rather than the constant profile as appropriated for the t ^ { -5 / 3 } accretion law .
Detailed modeling indicates that the total fallback mass is \sim 0.2 M _ { \odot } , with an ejecta mass M _ { \mathrm { ej } } \simeq 21 M _ { \odot } .
We find the third peak of the light curve can not be well fit by the fallback model , indicating that there could be some extra rapid energy injection .
We suggest that this extra energy injection may be a result of a magnetic outburst if the central object is a neutron star .
These results indicate that the progenitor of iPTF14hls could be a massive red supergiant .