Guardians Of The Galaxy made Groot – the Flora Colossus from Planet X – an instant icon, thanks to excellent motion capture work and the vocal stylings of Vin Diesel. The events of that movie led to something of a change for the character in Guardians Of The Galaxy Vol 2., though – with him having been, essentially, re-grown from a cutting.

As a result, Groot was seen as a child in both size and intellectual capacity. In the post-credits sequence, however, we caught a fleeting glimpse of teenage Groot, sulking about being lectured on room tidiness – and it’s this size in which he appeared in Avengers: Infinity War. Yes, in Joe and Anthony Russo’s event movie to end all event movies, Diesel’s fan favorite was all grown up, though by the end of the film, he was wiped out by Thanos’ snap of doom, along with most of the other heroes.

If you’ll recall, we see Rocket walking towards his best friend as Groot begins to turn to dust. Before he does, though, he lets out one, final “I am Groot.” Unfortunately, Bradley Cooper’s raccoon doesn’t translate it for us – as he usually does – but thanks to James Gunn, we now know what the character was saying, and it might just break your heart. Are you ready for this?

According to the writer/director, Groot’s final word to Rocket was “Dad.” As if the scene wasn’t heartbreaking enough, we now know that not only did Rocket have to watch his best friend be erased from existence, but that the little guy also saw him as his father, which no doubt makes the loss of Groot that much more painful for the only surviving Guardian of the Galaxy (well, aside from Nebula). We’re not crying, you’re crying!

Of course, we fully expect for Groot – and most of the other heroes – to return in time for next year’s Avengers 4. After all, when it comes to Vin Diesel’s character in particular, he sells WAY too much merchandise for Marvel to keep him dead for very long. And though that does lessen the impact of his death in Avengers: Infinity War somewhat, it was still quite sad seeing him go, and it’s only made all the more tragic now that we know what his last line was.

James Gunn Reveals Groot’s Heartbreaking Final Line In Avengers: Infinity War