This is a foreign god that Abimelech (Gideon's son) worshipped.
Judges 8:33As soon as Gideon died, the people of Israel turned again and prostituted themselves to the Baals and made Baal-berith their god.
Judges 9:1Now Abimelech the son of Jerubbaal went to Shechem to his mother's relatives and said to them and to the whole clan of his mother's family,Judges 9:2“Please speak in the ears of all the leaders of Shechem, ‘Is it better for you that all seventy of the sons of Jerubbaal rule over you, or that one man rule over you?’ Remember also that I am your bone and your flesh.”Judges 9:3And his mother's relatives spoke all these words on his behalf in the ears of all the leaders of Shechem, and their hearts inclined to follow Abimelech, for they said, “He is our brother.”Judges 9:4And they gave him seventy pieces of silver from the house of Baal-berith with which Abimelech hired worthless and reckless fellows, who followed him.