What! was he to lose his hold over these boys, and that because he was unable to cope with a boy much smaller and younger than himself? Perish the thought!
2007 June 22, Grace Dent, The Guardian, G2, p. 3:
According to industry gossips, Richard and Judy may soon go their separate ways. Not maritally; no, perish the thought.
Etymology
From the obsolete transitive sense of perish, "to cause to perish", itself possibly from a misunderstanding of the subjunctive mood in set phrases (i.e. [may it] perish, the thought) taken as transitive.