Origin: Malay- Kayu literally means wood in malay and Referee Kayu is used as a chant to scold referees when they made incorrect decisions.
Referee Kayu could be often heard when one watches a live football match at a stadium. This often occurs when the referee made an incorrect or odd decision. Referee Kayu could refer to the Referee as being blind or wooden in the sense that they are dumb or stupid.
After the Referee gave a penalty to the away team when there was no contact between the players:
Home Crowd: “Referee you blind is it!!!! Kelong ah!!! Referee Kayu!!! Referee Kayu!!! Referee Kayu!!!!