The most common cause is overzealous application of force during the act of levitation, which can cause some forms of strangulation, or even death.
To create a levitation spell, the caster chooses their own target. In this case, the target is an opponent. They may also select a single “target-in-place” and “target-disturbing” spell effect (though the latter two may only be applied at level 2, if that is appropriate for the target).
How does the spell work? You levitate up to the target, causing them to float for a number of seconds equal to the caster’s level + the caster’s Constitution modifier (minimum of 10 seconds). For most forms of levitation, any body part can be used to support the target (such as a head or an arm. It is also possible for a spell to cause a levitation from a torso or leg, or even from the chest or head). Once a target is airborne and at least a full set of body parts, the target gains a jump boost of 10 feet for every 10 points by which the target’s effective Strength is less than your caster level. This is equivalent to a +5 bonus to all Strength checks.
What happens if I take the levitation spell to use on allies? If you use levitation on an ally or on another creature within 30 feet, all those creatures are levitated, along with the ally. If you then use the spell in other ways, you may be affected by the same effect as the target. If a target is affected by the magic of another target, both the first and the second target gain a number of positive levels equal to the greater number of negative levels the first target had, and your caster level is modified by the difference in levels between the two targets.
Can I use the levitation to control objects or others, such as a ring of levitation or a spider web? No, however, it is possible for the magic of levitation to be used on creatures not intended to function (such as if the targets are in an enclosed space).
Are any spells that affect creatures made by magic, such as entangle, or similar, automatically dispelled by the levitation spell? Yes. You must remove the effect or the object. You may use this feature on a target in a spot you can reach, if you are able to do so. You’re also limited with the number of times you can do this.