Trivia: Max von Sydow's costume for the Emperor Ming weighed over 70 pounds and he could only stand in it for a few minutes at a time.
Trivia: Sam J. Jones (Flash Gordon) had a falling-out with producer Dino De Laurentis in post-production, which resulted in much of his dialogue being dubbed over by another actor.
Trivia: The tree person that gets locked into the cage with Flash (Fico by IMDB credit list), that "stole" the key to the cage, is Richard O'Brien, who is known for creating the Rocky Horror Show.
Answer: Since one meaning of "bore" has to due with digging tunnels and they are used in the torture scene, one can assume that they are worms that eat holes into your flesh.