  We find a simple analytic solution in open string field theory which, in the
on-shell limit, generates a tower of higher spin vertex operators in bosonic
string theory. The solution is related to irregular off-shell vertex operators
for Gaiotto states. The wavefunctions for the irregular vertex operators are
described by equations following from the cubic effective action for
generalized rolling tachyons, indicating that the evolution from flat to
collective higher-spin background in string field theory occurs according to
cosmological pattern. We discuss the relation between nonlocalities of the
rolling tachyon action and those of higher spin interactions.
