Cultivate students who Horace Slughorn thought had potential or connections.
- "He used to handpick favourites at Hogwarts, sometimes for their ambition or their brains, sometimes for their charm or their talent, and he had an uncanny knack for choosing those who would go on to become outstanding in their various fields. Horace formed a kind of club of his favourites with himself at the centre, making introductions, forging useful contacts between members, and always reaping some kind of benefit in return [...] "
- —Albus Dumbledore on the Slug Club[src]
The Slug Club is made up of Horace Slughorn's most well-liked and sometimes famous students at Hogwarts School of Witchcraft and Wizardry. Professor Slughorn, who taught Potions at Hogwarts from the 1920s-1981 and again from 1996-?, sought students who were well connected, held fame, and/or showed true promise in some field(s) of magic.
These select students were invited to parties (such as the particularly lavish one held on the 20th of December, 1996) where Professor Slughorn would then weed them out further. He was sure to keep in touch with those who "made the cut", even after they had graduated, as they would oft provide him with useful information and/or various luxuries. 
Along the course of the school year, Professor Slughorn would hold various club get-togethers (most often dinners with fine food and around 10 student-attendees). Slughorn would lead the conversation in order to get to know the members better and encourage them to associate with one another. For the grander parties he would invite famous former members, such as professional Quidditch player Gwenog Jones.
Professor Slughorn's aim was to cultivate talent and give his favourites a nudge toward fame and fortune, hoping to reap the benefits of his connection to them once they became the "high fliers" he expected them to be . On the 20th of December, 1996, there was a lavish party for past and present Slug Club members held in Professor Slughorn's office at Hogwarts. It was the only get-together of the club that Harry Potter attended . After Harry's failed attempt to get a particular memory out of the Professor, Slughorn apparently stopped these meetings in order to prevent giving Harry another attempt.
It is unknown what became of the Slug Club under Severus Snape's Heamastership during the 1997–1998 school year. It may have been disbanded due to the return of Educational Decree Number Twenty-Four, though the decree technically only affected student-founded clubs (such as Dumbledore's Army). Under the Headmastership of Minerva McGonagall beginning in 1998, it likely that Professor Slughorn stayed on as Potions master and Head of Slytherin House at Hogwarts, and due to his nature the Slug Club was likely reinstated (if it was ever disbanded).
Slughorn's First Tenure as Potions Master
- Adrian – Class of 1978, became a photographer. 
- Alecto Carrow — A student from Slytherin House who attended Hogwarts sometime before Slughorn's retirement in 1981. Later became a Death Eater and presumably killed in the Second Wizarding War.
- Ambrosius Flume – Owner of Honeydukes, sends Slughorn sweets. 
- Avery – Member in the 1940s, became a Death Eater. ,
- Barnabas Cuffe – Editor of the Daily Prophet (as of 1996). 
- B. C. – Mountain climber. 
- Dahlia F. – (Unknown). 
- Dirk Cresswell – Former Head of the Goblin Liasion Office who had insider information of Gringotts, killed during the Second Wizarding War. 
- Eldred Worple – Writer of Blood Brothers: My Life Amongst the Vampires. 
- Gwenog Jones – Captain of the Holyhead Harpies (as of 1996-97). 
- Lestrange – Member in the 1940s, part of Tom Riddle's gang, became one of the first Death Eaters. 
- Lily Evans – A good student with particular talent in Potions. Murdered during the First Wizarding War. 
- Lucius Malfoy – Of the rich and influential Malfoy family, a Death Eater (until the end of the Second Wizarding War), a respected high-ranking Ministry of Magic official, and for a time a member of the Hogwarts Board of Governors. 
- Mr. Nott – Theodore Nott's father, who Slughorn inquired about and referred to as an old friend. 
- Regulus Black – Slytherin Seeker, later became a Death Eater (though he betrayed Lord Voldemort by trying to destroy Salazar Slytherin's locket, one of Voldemort's Horcruxes, and was killed in his attempt).
- Severus Snape – A good student who was brilliant at Potions and making new spells. Became a Death Eater, but defected. Succeeded Slughorn in the post of Potions master at Hogwarts . He was murdered by Tom Riddle in the Second Wizarding War. 
- Tom Riddle – A very promising student with excellent marks, later became known as Lord Voldemort, the most powerful dark wizard, killed during the Second Wizarding War. Slughorn told Tom the details of Horcruxes, which were key in his rise to power. 
- Unidentified individual – Class of 1967, became Minister of Magical Transportation. 
- Wendy Slinkhard – Writer, and kin to Wilbert Slinkhard.
Slughorn's Second Tenure as Potions Master
- Blaise Zabini – His mother is a beautiful witch who has wedded and been widowed at least seven times, thus inheriting a great deal of wealth from her former husbands. 
- Cormac McLaggen – His uncle Tiberius is well-connected within the Ministry of Magic. 
- Flora and Hestia Carrow. 
- Ginny Weasley – A popular student who caught Professor Slughorn's attention when she cast the seemingly difficult Bat-Bogey Hex on the Hogwarts Express. 
- Harry Potter – "The Boy Who Lived" and "The Chosen One", son of Lily Evans, a former 'Slug Club' member.
- Hermione Granger – the best student in her year.
- Melinda Bobbin – her family owns a large chain of apothecaries.
Students not accepted
- Marcus Belby – His uncle Damocles invented the Wolfsbane Potion, but Marcus had not spoken to him in a long while as his father and uncle were not on good terms. Belby was nevertheless invited to one of the club's supper meetings, but by the time of the Slug Club Christmas party, Slughorn had Belby passing out towels in the loo. ,
- Neville Longbottom – His mother and father (Alice and Frank Longbottom) were once well-known and loved Aurors, but Neville showed none of their talent in this field (presumably his adeptness for Herbology never came up in conversation). 
Both Marcus and Neville were invited to the initial meeting in Slughorn's cabin on the Hogwarts Express, but in the end both failed to pass muster.
Benefits for Slughorn
Helping others become famous gained him influence (such as being able to recommend the next junior member of the Goblin Liaison Office) and various benefits (such as free tickets to any Holyhead Harpies match or a box of his favourite crystallised pineapple). Horace forechose to obtain things he desired by using his connections to make his life comfortable and cosy, rather than obtain them directly. 
Benefits for Students
Being in the Slug Club is both an honour and an opportunity due to it's exclusiveness, and with Professor Slughorn’s connections they would likely have first-rate careers ahead of them (if they possessed proper talent to begin with).
Behind the scenes
- In Harry Potter and the Half-Blood Prince it is mentioned that there are two seventh-year girls. This may have been referring to the twins Flora and Hestia Carrow, who only appeared by name in the film adaptation of Harry Potter and the Half-Blood Prince. 
- Sybill Trelawney and an unidentified female teacher may have been members of the Slug Club.
- In LEGO Harry Potter: Years 5-7, Marcus Belby makes it into the Slug Club.
- It may be that Professor Slughorn thought more of Ginny Weasley after she began dating Harry Potter (his "crown jewel").
- Harry Potter and the Half-Blood Prince (First appearance)
- Harry Potter and the Half-Blood Prince (film)
- Harry Potter and the Half-Blood Prince (video game)
- Harry Potter and the Deathly Hallows: Part 2
- LEGO Harry Potter: Characters of the Magical World (Mentioned only)
- LEGO Harry Potter: Years 5-7
Notes and references
- ↑ 1.0 1.1 1.2 1.3 1.4 1.5 1.6 1.7 Harry Potter and the Half-Blood Prince - Chapter 4 (Hoarace Slughorn)
- ↑ 2.0 2.1 Harry Potter and the Half-Blood Prince - Chapter 14 (Felix Felicis)
- ↑ Harry Potter and the Half-Blood Prince - Chapter 5 (An Excess of Phlegm)
- ↑ Harry Potter and the Half-Blood Prince - Chapter 16 (A Very Frosty Christmas)
- ↑ 5.0 5.1 5.2 Mentioned on the Harry Potter and the Half-Blood Prince script released on the Warner Bros. Awards website
- ↑ 6.0 6.1 6.2 Harry Potter and the Half-Blood Prince - Chapter 17 (A Sluggish Memory)
- ↑ Harry Potter and the Half-Blood Prince - Chapter 23 (Horcruxes)
- ↑ 8.0 8.1 Harry Potter and the Half-Blood Prince (film)
- ↑ 9.0 9.1 Harry Potter and the Half-Blood Prince - Chapter 15 (The Unbreakable Vow)
- ↑ See this image
- ↑ 11.0 11.1 11.2 11.3 11.4 11.5 11.6 Harry Potter and the Half-Blood Prince - Chapter 7 (The Slug Club)
- ↑ 12.0 12.1 New original characters cast for Half-Blood Prince
- ↑ Harry Potter and the Half-Blood Prince - Chapter 11 (Hermiones' Helping Hand)
- ↑ Harry Potter and the Half-Blood Prince (film) - Chapter 16