  In the effective relativistic quantum field theories the energy region, where
the special relativity holds, can be sandwiched from both the high and low
energies sides by domains where the special relativity is violated. An example
is provided by 3He-A where the relativistic quantum field theory emerges as the
effective theory. The reentrant violation of the special relativity in the
ultralow energy corner is accompanied by the redistribution of the
momentum-space topological charges between the fermionic flavors. At this
ultralow energy an exotic massless fermion with the topological charge $N_3=2$
arises, whose energy spectrum mixes the classical and relativistic behavior.
This effect can lead to neutrino oscillations if neutrino flavors are still
massless at this energy scale.
