Tonton Streaming Dungeons & Dragons (1983) S1E2 - The Eye of the Beholder

The children come across a knight named Sir John, who helps save them when they are being chased by a giant scorpion. When Dungeon Master sends them to battle a beholder in a distant valley, the children decide the knight is the perfect person to accompany them. The only problem is Sir John, in reality, is an utter coward.