"He's a friend from work!" That line is reference to The Hulk Seeing The Silver Surfer in the Arena. During The Original Planet Hulk story, The Surfer (while under mind control) was forced to combat the Hulk. Hulk tried to reach out to surfer as a Friend and failed. After a bit of fighting, Surfer's mind control device was damaged the hulk Pummeled him. Beta-Ray Bill was used in the animated film due to movie rights. In the trailer for Thor: Ragnarok we see Thor in the Hulks place, and the Hulk

Hulk Vs. Beta Ray-Bill - Battles - Comic Vine

The Origin of Beta Ray Bill Who He Is & How He Became Worthy Weekly One Shot