In Season 1, Episode 8 of Marvel's animated Guardians of the Galaxy series, the Guardians had a particularly venomous encounter that resulted in carnage for the team's resident muscle/houseplant. After facing off with a Symbiote, Groot was reduced to a pile of sawdust. It wasn't long before the sentient tree was regrown by his teammates, but this incarnation was a far cry from the adorable Baby Groot of the MCU.
The episode opens with the Guardians exploring a network of mines on an unnamed planet, where they're suddenly attacked by a swarm of Symbiotes. As they carry out Star-Lord's daring escape plan -- stolen, in true Peter Quill fashion, from Indiana Jones and the Temple of Doom -- one of the Symbiotes latches onto Groot's hand. Realizing it's the only way to stop the Symbiote and save his friend, Drax cuts off Groot's arm (knowing Groot will be able to regrow it). The Guardians escape the mineshaft and Rocket manages to trap the aliens in his pocket dimension vial, but one Symbiote makes it onto their ship undetected.
When the Symbiote latches onto Groot, the only way to defeat it is by using sonic vibrations from one of Rocket's improvised weapons. Unfortunately, the vibrations prove as deadly to Groot as they are to the Symbiote and he is reduced to a pile of dust. Rocket is grief-stricken until Quill remembers Groot's lost arm, trapped with the Symbiotes in the pocket dimension. Set on saving his friend, Rocket enters the storage dimension and battles his way through the imprisoned Symbiotes to reclaim the arm.
At the end of the episode, the team regrows Groot from the salvaged arm. This is where things get a little grotesque: instead of growing a whole new body from where the arm was originally severed, the arm becomes Groot's new body.
As the crooked fingers unfurl on the severed hand, a small face is revealed, bound to the palm by a cluster of gnarled and twisted roots. The hand alone was an unsettling sight, eerily reminiscent of the monkey's paw of the classic horror story, but the addition of Groot's empty-eyed face protruding like a strange wooden growth within a mane of pointed fingers is more than a little disturbing. The shrill voice, long shapeless body, and sprouting skeletal arms don't help either.
Luckily for him, by the start of the next episode, Groot's body is fully regrown and he's back on his feet. But this brief glimpse of one of the less conventional ways Groot can regenerate from his own remains serves as a fun (if horrifying) reminder of just how strange and alien Groot really is.