Avatar in the modern world

"Dude, check this out." I say, kneeling down in the dirt.

"What is it?" a Christina asks, looking down.

"I don't know." I pull up a circular disk with unknown symbols on it.

"Looks like some kind of artifact. But not Native American. More like Aztec. How heavy is it?" Josh asks, walking over.

"10-15 pounds, here, check it out." I say, tossing it to him.

"Damn its heavy." Jessie says, stroking her fingers across the writing. "How old do you think it is? Looks older than Aztec times. I mean just look at it."

"I mean its just a guess." I say, taking it back. "Or maybe its aliens." I joke around. Suddenly, a red sphere inside it glows and all of a sudden it explodes, hitting us with fragments of the artifact, like a grenade, minus all the fire and explosion.

After a couple minutes I get up and look around at Christina and Josh. "Are...are you guys...ok?" I ask, sitting up. I see my clothes and skin covered in lacerations. "Oh god...this is painful."

"Jay...are you ok?" Christina asks as she struggles to get up.

"What was that?" Josh asks, coughing up some blood. I notice a chunk of that thing in his neck.

"We...we need to go to the hospital or something." Jessie says.

"Yeah...but...oh god, my head is spinning." I say, trying to get up but tripping over a log.

"Jay?! Whats happening to me?" Christina asks, in a scared voice. I turn my head to see her hands are on fire. "Jessie? Josh? W-w-w-w-what is this?"

"Speak for yourself, rocks are freaking flying around me." Josh says, holding himself.

"Here, let me help you." Jessie says, reaching towards Christina, only to send a small jet of water at her.

What the hell is happening to them?

"Jay, look at yourself." Christina says, pointing at me. I look at myself to see a ring of water, earth, and fire spinning around me.

"Oh god...I...what do I do?" I ask, getting scared. Suddenly, everything goes black.