Turns out, with great power comes great power-hungry bad guys!
The Echidna Tribe are the opening antagonists of the 2020 live-action film Sonic the Hedgehog, which is based on the blockbuster videogame series of the same name developed by Sega. They are a tribe that seeks to obtain a great power source or lifeform for their own purpose.
Prior to the film, back when Sonic still lived with his caretaker Longclaw, the tribe attacked them one day. They likely did so because they knew of Sonic's existence, and thus they had secretly tracked down the hedgehog. When they finally confirmed Sonic's home location, the tribe decided to attack him, only being obstructed by Longclaw and repelled.
However, as Longclaw took Sonic to safety, one of the tribe bowmen shot an arrow that hit her, causing the tribe to run towards Sonic to either capture or kill him. Realizing that she would possibly be killed but that Sonic could still be saved, Longclaw gave Sonic a bag of portal rings and send him to Earth while she stayed behind retaining the Echidnas. Sonic did so and the portal closed, foiling the Echidnas' plan. Whether the tribe killed Longclaw or not remains unconfirmed.
The tribe was never seen for the rest of the film, but during a post-credits scene, a fox from Sonic's world named Tails tracks him down to Earth and expresses his hopes that it isn't too late to find Sonic, hinting that the tribe is still seeking Sonic during nowadays.
One of the Echidna Tribe members,where it attempted capture Sonic with a bag.
Sonic the Hedgehog (2020) - Young Sonic Scene (1 10) Movieclips
In the video game, the tribe's species were same with Knuckles the Echidna, who is famously one of the main stars in Sonic game. Their appearance may tease the appearance of Knuckles in the upcoming Sonic the Hedgehog film sequel.
It is unknown why the tribe wanted to catch Sonic, but since the film is (likely) a prequel of the games (or, at least had the same setting with the games), they possibly view Sonic as a force to protect the Chaos Emeralds in the game.
However, given when Sonic gets more emotional, his power grew even more than his normal state (the clan likely notice this), it can also be assumed the Echidnas view Sonic as a threat to the Emeralds and attempted to kill him.
Many fans thought that Knuckles appeared within the Echidna Tribe, given the extreme resemblance these Echidnas have to Knuckles. But this is impossible, since considering the history of video games, Knuckles is almost the same age as Sonic.