Im pretty sure Freddy has influenced the real world in every movie in the series, Stop being such a Humanoid SlouchyPaul

Is Freddy causing the house to be so hot
Yes, he is. You know how Ghosts typically make a house cold? Well this is Freddy and he makes it HOT(for obvious reasons)! The heat is used to imply when someone/thing is dreaming.
that a bird explodes? I always thought Freddy did stuff when people are dreaming but this movie confuses me.
"Shhh, they're sleeping". That should tell you everything you need to know. Freddy was testing out his possession skills with the DREAMING bird. He possessed the one to kill the other, but you can imagine, Freddy and all that heat/power?? A little bird doesn't stand a chance! So it exploded.
The bird scene is a trial run of sorts for what Freddy does to Jesse.
Who's strangling the cat?

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