Rosser sentence ($R\leftrightarrow \forall p({\mathrm{Prf}}_T(p,R)\to \exists q\le p{\mathrm{Prf}}_T(q,\neg R))$)

This diagonal sentence says that any proof of itself has a no-later proof of its negation. A proof of $R$ contradicts finite verification that no earlier opposite proof exists. A proof of its negation, together with finite verification that no earlier proof of $R$ exists, proves the displayed universal condition and hence $R$. Thus consistency alone excludes both proofs, strengthening the original omega-consistency form of incompleteness.