Fountain of Death
In Jerusalem Delivered, the hermit tells Charles and Ubald of a fountain, the sight of which excites thirst, but those who taste its water die with laughter.
Pomponius Mela speaks of a fountain in the Fortunate Islands, “ Qui potavere risu solvuntur in mortem.” Petrarch alludes to the same.
These fountains symbolise the pleasures of sin.
Source: Dictionary of Phrase and Fable, E. Cobham Brewer, 1894