Transparent, like heat waves
Repels Muggles from the charmed area
- Hermione: "Salvio hexia...Protego totalum...Repello Muggletum...Muffliato...You could get out the tent, Harry..."
- Harry: "Tent?"
- Hermione: "In the bag!"
- Harry: "In the...of course."
- — Harry and Hermione conversing while the latter casts enchantments such as this one.[src]
Some of the effects of the spell are that Muggles will suddenly realise a reason as not to enter the area over this charm's protection, for example, by "remembering" that they had an urgent appointment somewhere else.
Hermione Granger often cast the spell in the area when she, Ron Weasley, and Harry Potter went into hiding in during their hunt for Lord Voldemort's Horcruxes. Fantastic Beasts and Where to Find Them (real) also mentions that Muggle-repelling charms are used on the habitats of some magical creatures, to prevent Muggles from discovering them. Overall, it's used with most magical areas or locations, to protect the wizarding world and it's identity from non magic folk, or Muggles.
It was cast on the stadium of the Quidditch World Cup and may also be one of the protective spells placed on Hogwarts School of Witchcraft and Wizardry, since it is known that if a Muggle looks at Hogwarts the only thing they see is a decrepit ruin with a sign saying "Keep out". It is also likely that it has been cast over St Mungo's Hospital for Magical Maladies and Injuries.
Behind the scenes
- When Harry is viewing the memory from Tom Riddle's diary in Harry Potter and the Chamber of Secrets, Tom says to Hagrid at one point: "The dead girl's parents will be here tomorrow." It is stated elsewhere in the book that Myrtle is Muggle-born. Muggles cannot enter Hogwarts. However, it is possible, that an exception was made for them (the Muggle-Repelling Charm could be lifted a day or two, for this reason).