- This is the only episode of the TV series that Pop stars in without causing the death of any characters (he may have indirectly killed Cub when he started whistling, though Cub may have just been injured).
- This is one of the few episodes where Pop is missing his pipe for the entirety of the episode.
- Although he does not live long enough to make use of the information, Lumpy's plan to identify Whistle by whistling actually works; of all the dogs in the van, Whistle is the only one who gets a bulging left eye. All the others have bulging right eyes.
- However, this only applies for this one scene.
- When Pop calls Lumpy, some of the sounds he makes sound a lot like Fliqpy.
- This is the first time the sun has gone down in a TV episode.
- This is one of four episodes in the TV series where Lumpy is killed by animals (the other three are Take a Hike, Mime to Five and Letter Late than Never).
- Mime is the only character whose death wasn't caused by either the Giant Squid or Whistle.
- This is one of the few episodes where The Mole does not kill or harm anybody despite being killed himself.
- This is one of five episodes where a thought bubble is used. The other four are Crazy Ant-ics, Can't Stop Coffin, As You Wish, and And the Kitchen Sink.
- If one notices, Lumpy appears to be sad over the deaths of Lifty and Shifty.
- When Lumpy realizes his net is destroyed, he clearly says "What the f*ck?".
- This is one of the few episodes where one of the starring characters (Cub) dies early (Debatable).
- Throughout the episode, the things that set Whistle off include:
- Pop's whistling
- A bird's tweet
- A tea kettle
- Mime's whistle (five times)
- Lumpy's whistling
- Pop and Cuddles are (Debatably) the only survivors of the episode, and are also the only survivors of Sea What I Found and Letter Late than Never.
- When Giggles giggles at Whistle, she sounds exactly like Petunia when she makes the same giggle in I Heart U.
- When Giggles is being killed by Whistle, she screams the same way Cub did in Water Way to Go just before he died.
- The YouTube thumbnail for Part 1 spoils one of Giggles' injuries before death.
- Nutty, Flaky, Russell, Cro-Marmot, Flippy, Splendid, Lammy and Mr. Pickels are the only characters who don't appear in this episode, with the last two being more obvious.
- Nutty's scream can be heard when Lumpy sets up his mousetrap for single-handedly disables the giant squid.
- The title of this episode is a common phrase said when you realize a mistake you made.
- Whistle tearing Giggles' skin off her buttocks is a parody of the Coppertone sunscreen logo.
- The moral of the episode, "Let sleeping dogs lie", means to not disturb.
- Mime's death is similar to Handy's death in A Bit of a Pickle.
- Disco Bear's injury before death is similar to Russell's injury in Idol Curiosity.
- When this episode aired along with Concrete Solution and Sea What I Found on YouTube, the alternate title for the conglomeration of the segments was named "The Third Degree." Lifty, Shifty, Pop, Cub, Cuddles, and Lumpy, appear in all three episodes. Lumpy and (Debatably) Cub die in all three episodes they appear in, Lifty & Shifty die twice, Cuddles (Debatably) dies once and Pop survives in all three episodes.
- Whistle is based on Ken Pontac's dog of the same name, who also provides Whistle's voice.