The spitting spiders, and the mechanism is the genus: a venom-and-silk spray fired in a zigzag to pin prey at range, the only hunting method of its kind in the hobby.
Slow-moving, long-legged, delicate, and harmless to keepers, which makes the genus a rare combination: genuinely novel behaviour at zero risk. Small dry housing, small prey, and patience for a nocturnal performer.
Supply is thin and incidental, part collection and part accident, and the trade is curiosity-sized. The spit justifies the shelf space and the price stays where novelty-without-scarcity always leaves it. One of the site's few entries where the behaviour is the entire product and delivers.