Many moons ago, before the Castillian was banned as a dive site, I was wrestling with swag in 12 m, vis was 15m at least, so really daylight down there. Anyway I noticed a strap conger swim past me and thought the "that's unusual-free swimming etc" thought. A few mins later another one and soon after another... I looked round and saw Elfyn about 10m away looking like Medusa with around a dozen of the buggers circling just above him- the cause of that one was obvious... he had a nose-bleed and kept snorting the blood out of his mask. Impressive site, made it an unforgettable dive
Impressive too, the sense of smell on the critters.
Thinking about it, Conger encounters seem to be in a fair chunk of most memorable dives-
Surprise! 
ATB,
Terry