This spell attempts to transfer a magical effect from a creature you touch to yourself. When you touch the creature, siphon magic attempts to end one ongoing spell that has been cast on that creature, as if via a targeted dispel magic. If you know the specific spell effect you wish to target, you can name that spell effect to target that specific spell; otherwise siphon magic begins with the highest-level spell in effect and works its way down through all spells affecting the target until it dispels one or runs out of effects, as per dispel magic.
If siphon magic successfully ends a spell effect on the target, the remaining duration of that spell effect is transferred to you. That spell effect plays out for the rest of its duration as if you had been the original target. If the spell allows a saving throw to resist the effect, you gain a saving throw as if the spell were just being cast upon you, although this does not “reset” the spell’s duration.
Pathfinder Campaign Setting: Inner Sea Magic. © 2011, Paizo Publishing, LLC; Authors: Jesse Benner, Jason Nelson, Sean K Reynolds, Owen K.C. Stephens, Russ Taylor.