Bleeding Spines Snare

When a creature enters the square, thorny spines protrude out to stab it, dealing 8d8 piercing damage and 2d8 persistent bleed damage. The creature must attempt a DC 31 basic Reflex. After the initial trigger, the spines retract and protrude again repeatedly for 1 minute, forcing any creature that enters the space or ends its turn in the space to take damage from the spines (attempting the same basic Reflex save).