The jellyfish floats on the surface, or just beneath it, dangling its long poison-filled tentacles deep in the water to stun fish that accidentally brush against them. When the swimmer comes in contact with one he is rewarded with a sharp searing pain, usually in a ling line that reddens and forms a welt. The full effect of the burn does not become evident until four or five hours later. The pain can reduced by bicarbonate of soda or a steroid cream rubbed gently over the affected area. Even then it will continue to hurt and may leave scars.