Palacus or Palakus was the king of Lesser Scythia who succeeded his father, Skilurus

Skilurus

Skilurus or Scylurus was the best known king of Scythia in the 2nd century BC. He was the son of a king and the father of a king, but the relation of his dynasty to the previous one is disputed...

. Resuming the latter's war against Mithridates the Great, he attempted to besiege Chersonesos but was defeated by Pontic forces under Diophantus

Diophantus (general)

Diophantus , son of Asclepiodorus, of Sinope, was a general in the service of Mithridates VI of Pontus. Diophantus was active in Mithridates' campaigns in the Bosporan Kingdom and elsewhere around the Black Sea, although their chronology is disputed...

. Enlisting the assistance of the Rhoxolani

Rhoxolani

The Roxolani were a Sarmatian people, who are believed to be an off-shoot of the Alans. Their first recorded homeland lay between the Don and Dnieper rivers; they migrated in the 1st century BC toward the Danube, to what is now the Baragan steppes in Romania.The Greco-Roman historian Strabo ...

 under Tasius

Tasius

Tasius is the name given by Strabo to the king of the Rhoxolani, a Sarmatian tribal group. Around 100 BCE, Tasius led an invasion of Crimea in support of the Scythian warlord Palacus. He was defeated by the Pontian general Diophantus....

, Palacus launched an invasion of the Crimea

Crimea

Crimea , or the Autonomous Republic of Crimea , is a sub-national unit, an autonomous republic, of Ukraine. It is located on the northern coast of the Black Sea, occupying a peninsula of the same name...

. The invaders were defeated by Diophantes and accepted Mithridates as their overlord. Palacus was the last Scythian king whose name is attested in classical sources.