Banjo and Kazooie

Banjo and Kazooie are two Vortigaunts that appear in Half-Life: Opposing Force.

Overview
The level creators and developers of Opposing Force used often humorous entity names for the enemies, allies, maps, weapons and objects, two of them being the two vortigaunts. The vortigaunts were named after the highly acclaimed platormer Banjo-Kazooie. The entity name for both were made as a joke by developers as they developed the game.

List of Appearances

 * Half-Life: Opposing Force (First Appearance). (Game Files only).

Reference

 * https://www.youtube.com/watch?v=id_oF87YV5Y