Earthbind

Yellow strips of magickal energy loop around the creature, preventing flight. Choose a creature that you can see within range. The target must make a Strength saving throw.

Critical Success (+10). The target is unaffected.
Success. The target falls safely up to 20m and the spell ends for them.
Failure. The target's flying speed (if any) is reduced to 0m for 1 minute. An airborne creature affected by this spell safely descends at 20m per round until it reaches the ground or the spell ends.
Critical Failure (–10). The target's flying speed (if any) is reduced to 0m for 1 minute.

At Higher Levels: Increase the number of targets by 1 for each spell level increase. The additional targets must be within 10m of the original target.

A very nifty spell for those annoying flying creatures.