  We suggest that the ultraluminous X-ray sources located in external galaxies
(ULXs) are supercritical accretion disks like that in SS433, observed close to
the disk axis. We estimate parameters of the SS433 funnel, where the
relativistic jets are formed. Emergent X-ray spectrum in the proposed model of
the multicolor funnel (MCF) is calculated. The spectrum can be compared with
those of ULXs. We predict a complex absorption-line spectrum with broad and
shallow K$\alpha$/Kc blends of the most abundant heavy elements and particular
temporal variability. Another critical idea comes from observations of nebulae
around the ULXs. We present results of 3D-spectroscopy of nebulae of two ULXs
located in Holmberg II and NGC6946. In both cases the nebula is found to be
powered by the central black hole. The nebulae are compared with SS433 nebula
(W50).
