Visible crew/equipment: When Flash is attacked by the alien he falls on a noticeable brown safety mat.
Flash Gordon (1980)
1 visible crew/equipment mistake - chronological order
Directed by: Mike Hodges
Starring: Max von Sydow, Sam J. Jones, Topol, Melody Anderson
Continuity mistake: The egg timer in the jail is about to run out, but when Dale runs over to it and tries to turn it over, there is more sand in it than before.
Dr. Hans Zarkov: We are only interested in friendship. Why do you attack us?
The Emperor Ming: Why not? Pathetic earthlings. Hurling your bodies out into the void, without the slightest inkling of who or what is out here. If you had known anything about the true nature of the universe, anything at all, you would've hidden from it in terror.
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.