When you bring your little lantern pet, or anything that gives off charge, into the area of a seeker, the seeker will double in damage and speed and will aggro towards you until the source of charge has depleted. Oh and they spawn in big numbers, so run for your life.
Someone tipped they can't be found on Valguero...Not true...Official server, single player I've found dozens roaming the depths of the Aberrant cave!!! Then force tamed a level 145 & 100% imprint. Nice tame!!!