Real or unreal

I meet kids every week since I started to teach English, but still, they've been "mysterious" to me.
Especially, Makoto and Takuya, in my 4-5 years old class!!
They are always kicking each other, running in the classroom, or trying out from the room.
However, today, a thing happened that made me felt, "Yeah! I caught them!!"

While they were screaming as usual in the class, they noticed the unusual sound.
One of the fluorescent lights almost run down, so it made a buzz.
When they heard it, they shouted.
"Keiko sensei! It's a spaceman! The spaceman is signaling!! Scary!!"
They hid behind me.

I hit on an idea.
I said, "Yes, exactly! The SPACEMAN is watching YOU!! If you don't study English here, they will appear soon! Do you understand?"
They were still shivering and nodded. "We got it!"

"Good boys! Let's sing, Head, shoulders, knees and toes!"
Usually, they ignored me and kicked each other when I sang the unit song.
However, today, they watched my gestures seriously, and sang out loud!
After we finished the song, the buss sound became slower because it was finally about to run out. Then. they shouted again.
"Listen! Keiko sensei!! Isn't he applauding??"
I pretended to be surprised, exaggeratedly.
"Yes, he is! Wow! It's the first time! Because you sang the song very well, he is applauding to you! Good job, Makota and Takuya! You are so special!!"
They looked very glad. "Yeah!! We are so special!!"
...Until the class was over, they were like different boys as usual because of the "spaceman's effect."

After the class, I told them in front of their mothers.
"The spaceman was watching us today! But you did a great work, so he was applauding to you, wasn't he!?"
...Then, the kids said.
"Yeah! Or, you have been using the electricity too much, haven't you?"

...What!? They had said very unrealistic thing, but suddenly they became so realistic!! Did they pretend to adjust me???
They are still mystery...