The goblins are creatures who like to do things for a reason, not be unpredictable. For these reasons, the Goblins are very wicked creatures, and usually aren’t unpredictable.
The goblins’ songs are similar, but may say opposite things about the goblins. In Chapter 4 “Over Hill and Under Hill”, the Goblins sing a song full of onomatopoeia that goes with their actions. This song is similar to the song in Chapter 6 “Out of the Frying-Pan into the Fire” because both songs the Goblins sing describe their actions. When the Goblins say “Swish, smack! Whip crack! Batter and beat! Yammer and bleat!”, that is what the Goblins are actually doing to Bilbo and the dwarves. Later in the book, they say ”Burn, burn tree and fern! Shrivel and scorch! A fizzling torch