3 Year Old Suddenly Saying (Not Doing) Violent Things...

Please read this:
http://www.scholastic.com/resources/article/when-good-kid...

He is not abnormal.
Developmentally, kids go through stages of concepts.
Both girls and boys.

I have a son.
I also have a girl.

My son went through that, and goes through that. BUT... as they get older developmentally, their understanding of abstract concepts of this, gets more articulate.
Your son is only 3.
Kids this age, don't even have fully developed emotions yet, nor social skills. They are... still, learning. They not being fully mastered at these skills or aptitudes, yet.
But now and as he gets older, you guide him and talk with him.

Bear in mind, boys play in a different way, than girls.
They are more physical and make more special effects type sounds.
It is not only... about what they watch on tv.
It is also a form of pretend-play.
That is ALSO how a child learns... about the world and about concepts.

It is, developmental based.

Just because a boy, pretend plays this way, does not mean he is not sweet nor a nice boy.
They are only 3. They are not masters, of understanding yet. Not even Teens are.
He is young. Just guide him and talk with him. Most times, they are not even knowing it is inappropriate. So you guide... the child.

But teach him that certain words, are very... unsafe. Not for fun.

Even if he is picking it up at school, you still need to guide him. Sure tell the Teacher. But any mix of kids in a classroom, you will get all kinds of kids saying different things. Thus the emphasis, on guiding your child. So they can make their up their own mind... not being a "copy cat."
As he gets older, he will understand, more.

Kids are parrots.
So again, guide your child and teach him, what is right/wrong, or nice/not nice.
As you said, he giggles after he says it. Kids this age, don't even know... "correct" reactions to things like this. They are still developing emotionally. They don't know what to make of it.

Boys... play different, make different sounds, say different things from a girl, and per pretend play.
Boys... also (as a head's up), have humor using potty mouth jokes. They like to talk about poop and boogers etc.
But this is not, abnormal.
It is simply, funny, to them.

As he gains in age and in cognitive and emotional awareness and maturity.... he will be more apt to be able... to gauge himself and his words. Per how you guide, him.

Also know: that your son is NOT NOT NOT, the only boy... who does this.
;)

Yes, as others say it's a normal thing for kids this age, especially boys, to "play this way," but I don't believe that means you should just let it go completely. Your reaction so far with him sounds great.

Talk to the preschool about his day and the other kids, and especially find out if the preschool ever uses TV to calm the kids down or keep them busy while adults do other things. NO preschool should ever use TV or videos like that. If it's a special ed preschool he should be getting adult attention and if you find they are sticking the kids in front of TV "just for a minute" as they get ready to change activities, etc., I would find out if they use specific videos or if they just turn on any old animated show; if it's the latter, the kids could be watching anything. (My godson came home from day care with a lot of talk that his mom found out came from the day care provider just letting the TV babysit the kids, and it was whatever Batman/superhero/non-educational junk happened to be on any old channel.)

If TV at the preschool isn't the culprit, then he is hearing this from other kids. I would let the teachers -- and the director -- know you're hearing this; that it is a sudden and big change for him, not some gradual or small thing; and that you believe he's hearing it from other kids there. I would emphasize that you know it's typical for kids this age to talk like this BUT do the adults handle it, and how? Do they redirect kids, or tell them all consistently that these kinds of statements (I''ll stab you, I'll shoot you) are not acceptable? And do they follow through somehow if a kid keeps using them? I know it's different if these are kids with special needs but there has to be some kind of consistent decision on how the adults respond to these phrases when they crop up. You don't want to be the "goes ballistic about every little thing" parent, and you don't have to be the "boys will boys parent." You do not have to just sit back and accept that your son should come home talking in ways that you consider unacceptable.

Your replies to him so far are just great -- "big owies" and asking him to substitute "hugs" instead. Terrific for his age. Maybe the teachers can do the same kind of response.

Oh yeah... sure. Cops and Robbers. Knights and Castles. Chasing games where the kids are running around saving the world, and whose "side" you're on changes every 30 seconds.

Then there's also Doctor games... where kids are performing surgeries on each other or themselves or a doll

((SUPER common with medical issue kids. It's sooooo cute to hear the toddlers talking in the playroom at children's.

"Okay, I'm going to make an incision."
"What's an incision?"
"It when I slice you open and your insides fall out! It makes you better. But first a poke!"
"Okay. Decision me!" pause "You'll put my insides back. Right?"
"Yep. But I think this part should be here, and that part there."
"I want my feet on my head, and my hands where my feet should go!"))

Yeah. DEFINITELY talk to the teacher. It's probably totally innocuous, like one of the above save the world or save a life game... but it would be good to have the context of it. ESP with a verbal delay. So you can play along.

Unfortunately, he probably is picking it up at school..... even though you watch what he sees on tv, etc, there are plenty of people that don't monitor the tv... they are probably picking it up from there.

Even innocuous movies that parents might "allow" their younger ones to watch/hear have phrases like that in them. Or, as they (the parents) are watching a show, they may not realize what their little ones are hearing and seeing, thinking that they are involved in play somewhere else.