  We describe new scenarios of generating curvature perturbations when inflaton
(curvaton) has significant interactions. We consider a ``spot'', which arises
from interactions associated with enhanced symmetric point (ESP) on the
trajectory. Our first example uses the spot to induce a gap to the field
equation. We observe that the gap in the field equation may cause generation of
curvature perturbation if it appears not simultaneous in space. The mechanism
is similar to the scenario of inhomogeneous phase transition. Then we observe
that the spot interactions may initiate warm inflation in the cold Universe.
Creation of cosmological perturbation is discussed in relation to the inflaton
dynamics and the modulation associated with the spot interactions.
