Sidney "Sid" the Sloth is one of the three main protagonists of the Ice Age franchise. He is the best friend of Manny.
- He became nothing but a stereotypically lazy bum during these films, especially Collision Course.
- He is even more gross than he was in the first three films, such as vomiting out prune jelly, which leaves Manny and Diego understandably disgusted to the point of looking away, wiping his face with poison ivy, and so forth.
- Sid finding a mate, while a fine concept on paper, was very pointless and poorly executed, especially in Collision Course.
- In Continental Drift, he was careless to the point that he ate a fruit that paralyzed him without knowing it.
- Like Manny, Sid received even more flanderization in Ice Age: Collision Course and became even more idiotic and an even bigger butt-monkey than he already was. Not helping is that while Manny got his original personality back in The Ice Age Adventures of Buck Wild, the same can't apply to Sid in the same film, this is explained further in BQ#7.
- He is also more destructive than he was before as well, like when he (accidently) destroyed Geotopia just so he can give a diamond to Brooke.
- He acts even more out of character than he already was in The Ice Age Adventures of Buck Wild due to receiving even worse flanderization than he had in both Continental Drift and Collision Course:
- He shows little to no care for Crash and Eddie whatsoever, to the point of making inconvenient and tasteless comments about them being dead, such as "I don't mean to be a negative Nancy, but they've been gone a while. Shouldn't we just be looking for bones at this point?", "Face it, guys. Crash and Eddie have gone bye-bye. They totally disappeared without a trace!", which he would have never said in the first three movies (and fits more to Crash and Eddie instead, since both of them said something similar to that in Dawn of the Dinosaurs).
- He also ruins all the emotional moments the movie tries to have, such as Ellie's backstory about Mother Opossum and Ellie's encounter with the possums at the end by saying "You know, I lost my mama too. Well, technically, she moved away without leaving a forwarding address. But then I found Manny here. And then, when Diego came along and tried to kill us, we knew we were destined to be a family!" (If this was supposed to be a joke, it came off as cringe-worthy), and "Aw. I love family reunions. But there's no buffet, so time to head home!" (Let Ellie reunite with her brothers peacefully, please).
- While the rest of the new cast members sound similar to the original voice actors, Jake Green, his new voice actor, sounds absolutely nothing like John Leguizamo. He sounds a bit more feminine, higher pitched, and more lispy compared to his original voice in the series and his screams became very annoying, though this is probably due to Leguizamo being busy with the well-received Disney film Encanto at the time, voicing the character Bruno Madrigal.
- While his design is still pretty good since nothing changes, some of his facial expressions in The Ice Age Adventures of Buck Wild can be hideous and uncanny due to the animation provided by Bardel Entertainment (which also animated the Disney+ Diary of a Wimpy Kid movies, Teen Titans Go!, Rick and Morty, Rainbow Butterfly Unicorn Kitty, 44 Cats and All Hail King Julien), similar to the Powerpuff Girls in the 2016 reboot.
- Just like the previous films, his design doesn’t really seem to replicate the design of actual giant ground sloths unlike how Manny and Diego's designs replicate woolly mammoths and saber-toothed tigers.
- Sid was a much more likable and funny character in the first three films. If you ignore his flanderization, he can still be likable and have his original personality for the most part in these movies.
- John Leguizamo still did an amazing job voicing him in both the fourth and fifth film.
- The Ice Age franchise would not be as good as it is without him
- He gave us a few funny moments from Continental Drift such as the scene where his face gets deformed from drinking saltwater and "Holy Crab"!
- In Continental Drift is revealed that he can communicate with the hyraxes in a foreign land, which is an interesting addition, and it helps push Manny's plan of action forward in successfully stealing the pirate ship from Captain Gutt and his crew, it shows that there are times where Sid is very useful in some situations.
- He also helps in the final battle against the pirates during the climax alongside his grandmother and Precious, and even helps save Manny from falling to his death after defeating Gutt. This earned his long overdue share of respect from Manny, who usually looks down on him. So, for all of his faults, he is still at least useful.
- Even though it was poorly executed (as mentioned in BQ#3), the idea of him getting a girlfriend is a pretty good concept, especially considering that nobody from his biological family but Granny loved him and even abandoned him, so it makes sense that he deserves to have some company and make a family of his own, improving on his own family's mistakes.
- His backstory is rather tragic since he was constantly left behind by his family because they didn't care about him, which makes his flanderization even sadder.
- Despite BQ#8, his design is still good.
- On the official social network Ice Age pages, in an imaginary Sid's profile of a dating site, it's written that Sid is 30. Since the Herd Valley is listed as his residence, Sid "would have created the profile" between the fourth and the fifth movie. Assuming this information is true, Sid would have been only about 7-11 during the first film.