Well, it was real. I swear.

4 seconds sound clip from the E.T. the Extra-Terrestrial movie soundboard.

You can hear this line at 00:16:56 in the Blu-ray version of the movie.

Quote context

[...]

- What are you going as for Halloween?

- I'm not going to stupid Halloween.

- Why don't you go as a goblin?

- Shut up.

- It's not that we don't believe you, honey.

- Well, it was real. I swear.

- What are you going as, Gert?

- I'm going as a cowgirl.

- So what else is new?

- Maybe it was an iguana.

- It was no iguana.

[...]