THESE GUYS!!!
These were probably the first non-sharptooth antagonists I ever saw in the franchise as I saw the third movie after the second one. Maybe because I saw Pokemon with Team Rocket, but I liked the idea of rival gang or Trio that the protagonists have to overcome. I also liked that though they are bigger (like how they sang about it XD) they are still kids/teens at the end of the day with the movie acknowledging this when Littlefoot goes to help them. Hyp even get's a neat redemption arc when we find out why he is a bully with it tieing in with Mr. Threehorn's character arc. Nod and Mutt however don't get as much development as Hyp, being his lackies and all which is kind of disappointing. ^^' However these guys might be the first and only non-sharptooth "villains" to have an appearance in the TV show (quatations because they are more like redeemed bullies. XD)
Also I remember really liking their song, it gave off: "Oh yeah, we are bigger and you can't stop us!" kind of vibes when I first heard it. It made me want to see these guys lose... (Funny as the whole egg song in the second movie made me want to see Ozzy eat a egg. XD) It was the perfect song to represent the antagonists of the movie.
Personally though I see Hyp and his gang as redemeed, I feel like he and his friends could still be mischievous troublemakers in the valley. Them trying to interfere with whatever the gang has planned or mess with them, though being good hearted at the end of the day. Although I do see Mutt and Spike being good friends. XD This screenshot kind of supports that as it looks like Mutt and Spike are smiling at each other as if they want to say "Hello". XD