Velum Phantasma

At-will, standard action, concentration, DC 17+; you create a complex, animated illusion at a point within 120 feet. The illusion occupies up to a 30-foot cube and can depict any scene: marching soldiers, a raging fire, a fearsome monster, a collapsing bridge. It includes sight, sound, temperature (but not actual heat), and smell. The illusion is fully animated and can respond to its environment under your direction—you can adapt it each round as a free action.

• Creatures that interact physically with the illusion (touching it, being "hit" by it) can make an Intelligence save to disbelieve. Once a creature disbelieves, the illusion becomes translucent to them.
• DC +4: the illusion has limited autonomy; you can preprogram behavior ("if approached, roar and charge"), freeing your concentration.