Oh yeah, here (http://dndtools.eu/spells/spell-compendium--86/caltrops--3774/) is the caltrops spell description.<br/><br/>So, Adrian case he covers five 5'ft squares with it (he covers area towards the carriage and thus force woman and horses walk over caltrops and then struggle with tentacles which occupy spot where horses should be placed at). Caltrops also get +4 attack bonus to injure and it halves movement speed by half if they hit (up to large creature and horses are large). Ofc vampire or anyone with DR ignores this and I suspect woman to be fellow vampire.