In I Am Number Four, directed by D. J. Caruso (Disturbia) and produced by Michael Bay (Transformers), nine alien toddlers are sent to earth to escape an invading race bent on destroying their planet. The Mogs track the Loriens on earth but can only kill them in sequence. The focus is on Number Four (Alex Pettyfer), who lives as a teenager in Ohio. Like Superman, he's developed superhuman powers, including enhanced strength, speed, agility and telekinesis.

With nearly 800 vfx shots under the overall supervision of Greg McMurry (G.I. Joe: The Rise of Cobra), the work was divided between ILM, Entity FX, Hammerhead, Shade and Dive, among others.

"The vfx included demonstrating these powers as well as the large reptilian-type hunting dogs, the Pikens, which belong to the Mogs, and are used to chase down the kids," explains McMurry.

ILM (under the supervision of Bill George) did the creature work, which comprised around 65 shots. There are two species of Piken: the baddies, which McMurry describes as a cross between a giant reptile and a flying squirrel, which are about 8-feet tall, can jump large distances and have webbed wing structures between their arms and legs; and the good-guy Bernie monster, which morphs from a gecko into a beagle before transforming into the canine beast that holds its own against the Piken in saving the alien kids.

"The shooting of plates to put these in a realistic environment was quite a challenge," McMurry relates. "We set out wanting to make sure everything was photographed as naturally as possible; we didn't want all the breakage to be some post-production CG event. So with the help of Peter Chesney, the overall special effects supervisor, we crashed these [heavy objects] called 'bucks' through an actual block wall. And then ILM went in and animated the creature in place of the buck. So it was our goal to have that very gritty, interactive, real stuff. Every scene was staged and shot as if the CG creatures were actually there. We used a lot of motion control for those purposes, to do interactive breakage, when a creature would come across a room and knock something over We wanted ILM to use the least amount of computer-generated interactive elements as possible."

The telekinetic powers were done by Hammerhead, which "designed a special slant of people lifting things and moving things." There is also Number Four's special power of Lumen, the ability to generate light out of his hands and arms, and Hammerhead "did these large, powerful light beams that could do anything from just light up his way at night to burn something like a powerful laser. We tried to maintain an organic and natural aspect to it and not look like something mechanical."

Another effect occurs when the Mogs get killed: they turn to a crusty substance and evaporate called "ashing." Entity FX, under the supervision of Mat Beck, did this effect along with the teleport speed effect for Number Six (Teresa Palmer).