If the spider does not hit an enemy before reaching the target location, it re-targets and chases down a nearby enemy, prioritizing champions. The spider gains bonusmovement speed, based on its proximity to its target.
Spiderlings last until killed (they take 25% reduced area-of-effect damage but turrets will always prioritize them above melee minions and die by a single shot)
If Elise turns to Human Form after having summoned Spiderlings any remaining live ones will be stored as charges, and will be re-summoned when Elise turns to Spider Form with the same health they had left plus any gained from health regen.
Turning to Human Form while having maximum Spiderlings stored will reset the damaged ones' health.