Milo and Zack try to help Melissa overcome her secret fear of roller coasters.
Milo, Zack, and Melissa go to Lard World, where the boys anticipate going on a roller coaster until they discover that Melissa has a crippling fear of them. After confessing their own fears, Zack's of fish and Milo's of Chinese fingertraps, the pair vow to help her overcome hers. Meanwhile, Balthazar Cavendish and Vinnie Dakota are on their latest pistachio protecting mission, safeguarding a pistachio stand within Lard World itself by building a protective frame around the stand. Balthazar ends up doing all the work, and taking all the heat as various threats to the stand emerge.
Milo and Melissa end up on the roller coaster Greased Thunder, which becomes even more terrifying due to the effects of Murphy's Law. Balthazar and Vinnie succeed in protecting the stand from one threat, only for it to be taken out by a different threat after they've taken down the protective frame. Milo and Melissa survive the ride, and then depart with Zack. Meanwhile, the Lard World mascot Lardee Boy's, is jettisoned into space, and hit by the Aliens that were first seen in Going the Extra Milo.
For a full transcript of "Murphy's Lard", click here.
More extras appear in the background, including the man with a feminine voice.
There are also repainted characters from Phineas and Ferb.
In Southeast Asia, this episode was heavily censored, with many references to lard and pork blurred and deleted, due to the fact that lard and pork are forbidden from Islamic culture.
Unlike what Zack states, a purely random event, such as a rollercoaster landing in your backyard, isn't less likely to happen if it has already happened once.
And as some things are more likely to get struck by lightning than others, lightning can easily strike the same place twice, and may strike a tall building many times over during a storm.
The book the rollercoaster controller is reading when he sends Melissa and Milo on to Greased Thunder is the same book Milo was reading when he distractedly sat in the Brulee's RV in Family Vacation.
Dakota can play various instruments such as a harmonica, a theremin, and a clarinet.
Phineas and Ferb - The rollercoaster that destroyed Melissa's science project on the first day of summer was the same one from the premier segment and first episode of Phineas and Ferb "Rollercoaster".
AC/DC - when the three main characters start singing "thunder... thunder... thunder" it's an allusion to the rock band AC/DC which is famous also for the song "Thunderstruck".
Apocalypse Now - Both when Zack leaves his pontoon after being scared by a fish and when Milo leaves his raft after being scared of a Chinese finger trap, a voice-over of each character says "Never get out of the boat (or "donut"). Absolutely right."
Back to the Future - When Cavendish and Dakota appear with a flash, a musical sting very similar to that played during various points in the famous time travel movie series, alluding to their status as time travelers.
Grease - Greased Thunder sounds similar to Greased Lightning, a song used in the movie. In addition, Milo references the song.
When Cavendish and Dakota are talking to the pistachio vendor, in the background a woman's sweater changes color from scene to scene.