| Hit Dice: | 9d8 (40 hp) |
| Initiative: | +9 |
| Speed: | 50 ft. (10 squares) |
| Armor Class: | 19 (+4 size, +5 Dex), touch 19, flat-footed 14 |
| Base Attack/Grapple: | +6/— |
| Attack: | Swarm (2d6) |
| Full Attack: | Swarm (2d6) |
| Space/Reach: | 10 ft./0 ft. |
| Special Attacks: | Distraction (DC 14), wounding |
| Special Qualities: | Darkvision 60 ft., immune to weapon damage, swarm traits, vermin traits, water walk, wavesense |
| Saves: | Fort +6, Ref +8, Will +3 |
| Abilities: | Str 1, Dex 20, Con 10, Int —, Wis 10, Cha 8 |
| Skills: | Hide +21, Spot +4; racial bonuses |
| Feats: | Improved Initiative [bonus] |
| Environment: | Warm marshes |
| Organization: | Solitary, fleet (2–4 swarms), or flotilla (11–20 swarms) |
| Challenge Rating: | 5 |
| Treasure: | None |
| Alignment: | Always neutral |
| Advancement: | — ♊ |
| Level Adjustment: | — |
A swarm of beetle-sized insects armed with long, spiked suckers skitters across the brackish water toward you.
Swamp striders are predatory insects whose physiology allows them to “walk” on water as easily as on land. They mob large creatures, piercing them with their dangerously long stingers, consuming the blood that leaks into the water. Despite the swarm’s dangerous nature, humanoid races sometimes hunt swamp strider swarms, considering roasted striders to be a fine delicacy. An individual strider is 7 inches long and weighs ½ pound.
Like any swarm, a swamp strider swarm surrounds and attacks any living warm-blooded prey it encounters. The swarm deals 2d6 points of damage (plus damage from its wounding ability; see below) to any creature whose space it occupies at the end of its move.
Wounding (Ex): Any living creature damaged by a swamp strider swarm continues to bleed, losing 1 hit point per round thereafter. Multiple wounds do not result in cumulative bleeding loss. The bleeding can be stopped by a DC 10 Heal check or the application of a cure spell or some other healing magic.
Water Walk (Ex): Swamp striders can move across water as easily as on land. This ability functions as the water walk spell, except that it is an extraordinary ability and the swamp strider swarm actually touches the water rather than floating above it. A swamp strider swarm that is submerged will rise to the surface (as per the spell effect), but if it is forced to remain underwater for 5 rounds or more, it must make a DC 15 Fortitude save every round thereafter or perish.
Wavesense (Ex): A swamp strider swarm notices and locates any creatures within 30 feet as long as they are in the same body of water as the swarm.
Skills: Swamp striders have a +4 racial bonus on Spot checks. Swamp striders gain a +4 racial bonus on Hide checks when in swamps or wetland terrain.
Swamp strider swarms are deadly nuisances in the Crawling Swamp (in the Shadow Marches) and the Vile Marsh (in western Droaam). Dozens of swamp strider swarms surround the ruined keep atop Karthoon Tor, located in the Vile Marsh—drawn to the presence of the vermin lord that lairs there (see Vermin Lords in Eberron for more information).
Swamp strider swarms harry travelers passing through the Adder Swamp east of Luthcheq in Chessenta and frequently terrorize the denizens of the Vast Swamp east of Cormyr. Swarms of blind white swamp striders inhabit the Lightless Sea and other Underdark lakes and seas; these Underdark swarms have blindsight instead of darkvision.
Source: Monster Manual III, page 171.