Caltrops are tetrahedral items used for making ground hard to cover. They always land with a pointy bit sticking up. Handy for preventing pursuers from catching you, whether they are on foot, on horseback, or, in more modern cases, in a vehicle.
Origin of movie trope where impaled character pulls/pushes blade/spear further into body? - Movies & TV Stack Exchange
What are some pieces of medieval European equipment (an oversimplification I know but bear with me) that most of modern fiction leaves out? - Quora
How was the caltrop used in medieval times? - Quora
Twelve Red Lines (a One Piece SI fanfic), Page 10
The RPG glossary - LeadBelt Games Arena - Tabletop Wargames Venue
Kill Six Billion Demons » King of Swords 7-64
Acquisitions Incorporated - Flip eBook Pages 51-100
How was the caltrop used in medieval times? - Quora
owie's profile - Blogs
Caltrops video games (Tools theme)
Dysfunction Junction - TV Tropes
tvtropes random trope generator ― Perchance
Origin of movie trope where impaled character pulls/pushes blade/spear further into body? - Movies & TV Stack Exchange
Trick Bomb - TV Tropes