Echo!

a kid in an empty parking lot surrounded by buildings.
echo
it reverberates "echo"
Echo
it reverbarates twice (from two different spots) "echo, echo"
ECHo
"Echo, echo, echo"
ECHO "echo, echo, echo"

So the kid goes over to investigate.
Echo
"Echo, echo, echo, echo"
He gets to a corner or under a bridge on a bike path or something.
Echo
"echo, echo, echo"
he goes in a big metal or cement like tube.
Echo
"echo, echo"
He looks inside an old garbage can or something about that size.
Echo
"echo"
he finds a bucket or something about that size and yells into it. Deciding that this is where the echo is originating from.
So he takes it home with him.
When he gets back home, he puts it on his head and tries it out.
Echo
"echo, echo, echo, echo, echo"
He is in his own little echo world. His mom walks by and smiles, and you see his echo collection of several old hard hollow things that he has brought home before and stuck his head into to make echos.