Cruel James Gunn casually broke hearts in the middle of a thread about porgs.

The "Guardians of the Galaxy" and sequel director weighed in on a tweet asking fans to save one -- a "Star Wars" Porg or Marvel favorite Groot. In the middle of his arguments, Gunn revealed that the first Groot of "Guardians" Vol. 1 died, and the Baby Groot of Vol. 2 was his child.

That was news to many fans, who figured Groot was the same Groot, just changed.

Here's that part of the convo, to start:

Fans were shook. And Gunn was irritated by everyone being surprised by stuff we (apparently) should already know.

Some people seemed to already know. Fine. But since it was never quite spelled out so bluntly before this Twitter thread pitting cute fantasy creatures against each other, many did not know.

The "Guardians" will return in "Avengers: Infinity War," opening May 4.

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