Spider Egg

Spider Eggs are very fragile and will break when attacked. They will either release nothing, a Spider, a Poison Spider, a Tarantula at rare times and very rarely a Giant Spider. Spiders that come from those eggs will not puff like normal spiders do when taken away too far from their spawn point.
To break the Spider Egg, simply use the egg. See also: Spider Egg/Breaking Statistics
In Against the Spider Cult Quest these eggs have a 100% chance of releasing a Giant Spider.