  We show several distinct signatures in the magneto-response of type-II Weyl
semimetals. The energy tilt tends to squeeze the Landau levels (LLs), and for a
type-II Weyl node, there always exists a critical angle between the B-fileld
and the tilt, at which the LL spectrum collapses, regardless of the fileld
strength. Before collapse, signatures also appear in the magneto-optical
spectrum, including the invariable presence of intraband peaks, the absence of
absorption tails, and the special anisotropic fileld dependence.
