Grotesque decorations

The word grotesque comes from the Latin root "grotto", meaning a small cave or hollow. The original meaning was restricted to an extravagant style of Ancient Roman decorative art rediscovered and then copied in Rome at the end of the 15th century. The "caves" were in fact rooms and corridors of the Domus Aurea, the unfinished palace complex started by Nero after the Great Fire of Rome in AD 64, which had become overgrown and buried. When Nero's Domus Aurea was inadvertently rediscovered in the late 15th century, buried in fifteen hundred years of fill, so that the rooms had the aspect of underground grottoes, the Roman wall decorations in fresco and delicate stucco were a revelation. This launched a real revival of this decorative style especially fpr ceilings, columns and walls of important palaces.

Beautiful grotesque  staircase's ceiling in Palazzo Vecchio.

The decoration is characterized by the representation of fantasy creatures, often half animals, half human, of chimeras and monsters, often portrayed as thin and whimsical figures, which blend in geometric decorations and structured symmetrically, on a background of generally white or monochrome.
This had a great fortune in the Renaissance and in Florence we have some of the most beautiful examples in Palazzo Vecchio and the Uffizi museum.

Grotesque on the ceiling of the Uffizi Gallery in Florence