  We consider string theory vacua with tadpoles for dynamical fields and
uncover universal features of the resulting spacetime-dependent solutions. We
argue that the solutions can extend only a finite distance $\Delta$ away in the
spacetime dimensions over which the fields vary, scaling as $\Delta^n\sim {\cal
T}$ with the strength of the tadpole ${\cal T}$. We show that naive
singularities arising at this distance scale are physically replaced by ends of
spacetime, related to the cobordism defects of the swampland cobordism
conjecture and involving stringy ingredients like orientifold planes and
branes, or exotic variants thereof. We illustrate these phenomena in large
classes of examples, including AdS$_5\times T^{1,1}$ with 3-form fluxes, 10d
massive IIA, M-theory on K3, the 10d non-supersymmetric $USp(32)$ strings, and
type IIB compactifications with 3-form fluxes and/or magnetized D-branes. We
also describe a 6d string model whose tadpole triggers spontaneous
compactification to a semirealistic 3-family MSSM-like particle physics model.
