Calavera or Calaveras, the Spanish word for "skull" or "skulls" can refer to any of several different things:

The Celebrated Jumping Frog of Calaveras County, a short story by Mark Twain

Calaveras are a type of ditty poems written around the Dia de Los Muertos (Day of the Dead) where people mock celebrities, politicians or poke fun at each other.

Manuel Calavera was also the name of the protagonist in the LucasArts 1998 adventure game, Grim Fandango.

Calaveras is the name of a character in Sailor Moon manga and anime series.

Calaveras County, California

The Calaveras Fault, a geological fault located in northern California in the San Francisco Bay Area.

Calaveras Reservoir, California

Rancho Calaveras, California

Calaveras Big Trees State Park in California

Calaveras Lake in Texas

Calaveras Road

Calavera (comic) is an adult comic featuring a Mexican female assassin with razor claws named Francisca Calavera

Calaveras Valley, California

Calaveras are a type of traditional Mexican ornament/treat used on the Day of the Dead. They are primarily made of sugar and are shaped in the image of skulls- usually with colorful designs.