The first time each round a creature enters a trapped square or starts its turn there, the hazard makes a release attack against that creature. On a hit, the creature takes 2d10 bludgeoning damage and 1d6 slashing damage, is knocked prone, and becomes entangled until it Escapes or the hazard is disabled.

After the initial lash, the barrel rack slams down in a 10-foot line across the alley, creating difficult terrain and blocking movement through that space until removed. Creatures in the line must attempt a DC 25 Reflex save. On a failure they take 3d8 bludgeoning damage and are pushed 5 feet to the nearest open space; on a critical failure they take double damage and are pinned in place, immobilized until they spend an action to Escape.

If a creature critically fails a save against this hazard, loose lamp oil bursts from a shattered jug, splashing a 5-foot square. That square becomes slick difficult terrain and a creature that enters it or starts its turn there must succeed at a DC 25 Acrobatics or Reflex check, or fall prone.

The trapped alley section is a 10-foot by 20-foot zone chosen by the hazard's creator. Creatures in that zone have their movement hindered by clutter and the alley's narrowness. Any creature that tries to Rush through the zone must first succeed at a DC 25 Reflex save or trigger the lash.

If the hazard takes 14 or more damage from a single attack, the exposed mechanism is jolted. The next routine attack this round is made with a penalty of 2, but a critical hit against the mechanism automatically triggers the hazard's routine against the attacker.

Creatures that are Large or larger can force through the barrel rack with a successful DC 27 Athletics check, treating the passage as difficult terrain for the rest of the round even on a success.