Vine Trip (3.5e Spell)

A rock moves slightly, and the barbarian charging you falls down.

The target creature must succeed on a Reflex save or fall prone. Creatures targeted by this spell may choose to make a Tumble or Balance check in place of the Reflex save, albeit at a -10 penalty.

Vine Trip doesn't work on creatures who are more than 5' from any surfaces or unattended objects.