Those D--- Friesian Horses!

cheval-de-frise (shuh-VAL duh FREEZ) noun
plural chevaux-de-frise (shuh-VOH duh FREEZ)

1. An obstacle, typically made of wood, covered with barbed wire
or spikes, used to block the advancing enemy.

2. A line of nails, spikes, or broken glass set on top of a wall
or railing to deter intruders.

[From French, literally horse of Friesland, so named because it was first
used by Frisians who lacked cavalry.]

"Fold back the leaves of an artichoke and you discover ... more artichoke
leaves, at least until you come to the succulent, secret heart hidden
beneath a chevaux-de-frise of thistle-like bristle."
David Nelson; Gastronomic Adventure Unfolds Like an Artichoke;
The Los Angeles Times; Jun 21, 1991.

"On the land side, outside the battlements, are acres of chevaux-de-frise:
sharp rock slabs set vertically into the ground, making it virtually
impossible for a person to pass, let alone a horse."
Denise Fainberg; On Foot In Inishmore; The New York Times; Aug 1, 1999.

--From A.Word.A.Day

Is this what those rows of spikes in parking lots that puncture your tires if you're going the wrong way are called, too?