  Modern transient surveys now routinely discover flares resulting from tidal
disruption events (TDEs) which occur when stars, typically $\sim0.5-2$
M$_{\odot}$, are ripped apart after passing too close to a supermassive black
hole. We present three examples of a new class of extreme nuclear transients
(ENTs) that we interpret as the tidal disruption of intermediate mass
($\sim3-10$ M$_{\odot}$) stars. Each is coincident with their host-galaxy
nucleus and exhibits a smooth ($<10$% excess variability), luminous
($2-7\times10^{45}$ erg s$^{-1}$), and long-lived ($>150$ days) flare. ENTs are
extremely rare ($\geq1\times10^{-3}$ Gpc$^{-1}$ yr$^{-1}$) compared to any
other known class of transients. They are at least twice as energetic
($0.5-2.5\times 10^{53}$ erg) as any other known transient and these extreme
energetics rule out stellar origins.
