You may use the effect of "Burning Beast" to destroy a Spell or Trap Card on your side of the field.
If a monster equipped with "Burning Beast" attacks your opponent's Life Points directly, and "Robbin' Goblin" is the only face-up Spell or Trap Card on the field, the turn player chooses whether to resolve "Robbin' Goblin"'s effect first or resolve "Burning Beast"'s effect first. If the effect of "Burning Beast" is resolved first and destroys "Robbin' Goblin", then "Robbin' Goblin"'s effect is not applied because it is a Continuous Trap Card that is no longer in play.