Oh, Harry Potter. A magical world full of wonderful spells, creatures, and magical items. But is every item as useful as any other? What about the spells? While there are surely some that are useful beyond measure, there are also some that we have to question.
As is the case in the Muggle world, there are simply items that make us question the reason behind them. Maybe it’s human nature to create and invent things that we don’t need. Who knows? What we do know is that there’s a solid list to be made of the most useless spells and items from the world of Harry Potter.
Spell-Checking Quill
A spell-checking quill sounds wonderful, doesn’t it? However, we know that this quill isn’t as effective as one would hope. Ron learned the hard way that when the magic runs out of this quill, it’ll change words that were spelled correctly into horrible misspelled words and names.
If you’re somebody like Ron, odds are that you’re not going to notice the spell failing until it’s too late. Not exactly the sort of problem you want to be dealing with while prepping for finals.
Aberto
Aberto is a spell used to open doors. Yes, that is all it does. This spell probably wouldn’t have made the list, if not for the fact that there is a significantly more powerful version of this spell floating around. We’re looking at you, Alohomora.
Unlike Alohomora, Aberto doesn’t seem to open locked doors. It really just opens doors, presumably. If you’re capable of wandless magic and have your hands full, this spell might come in handy. Realistically, though, that’s it. As Queenie found, it's more of a last resort when more familiar measures don't work. Even then, it didn't work either.
Spellotape
Spellotape. It’s basically exactly what it sounds like: magical tape designed to fix things. However, its uses are rather limited. It can’t, for example, repair a badly damaged wand. It can tape up an enchanted book rather well, but still, wouldn’t a more specific spell have worked just as well?
The one major use for this item would be the fact that students would be allowed to use it outside of Hogwarts (we’re assuming since it isn’t a spell or wand work). In almost any other instance it would be best to do a proper repair of an item.
Ears to Kumquats
So, this spell may or may not actually exist. That mostly depends on how much you trust the Quibbler. This spell was hinted at it an issue of The Quibbler that Luna Lovegood was reading during Harry Potter and the Order of the Phoenix. Said issue required Luna to turn the newspaper upside down in order to learn the spell.
So, we don’t actually know if the spell itself would work. But even if it did, and assuming it acts as the description implies…it can’t be terribly useful. Can it?
Remembrall
A Remembrall is a ball made of clear glass. When the smoke inside turns a dark red, it means you've forgotten to do something. It sounds super helpful, right? Especially to those of us who struggle in that department, like Neville Longbottom. There’s just one problem: it doesn’t actually tell you what you’re forgetting. If you’re the forgetful sort, odds are that there’s more than one thing that you’re forgetting. So, good luck narrowing things down!
Neville proved how ineffective this item is, though he clearly appreciated the gift. Those who are observant will know that Neville seemed to be forgetting his school robes. Still, it's not always that obvious.
Lacarnum Inflamari
The spell Hermione used was Larcarnum Inflamari. Which roughly translates to ‘set on fire’ and ‘cloak.’ Seems a little… specific, doesn’t it? How many times would one want to set a cloak on fire? Is it something Hermione has needed in the past, or will ever need again? There's probably a reason why this spell doesn't exactly exist in Rowling's canon.
Mobiliarbus
While we’re on the subject of very specific spells, let’s cover another one that Hermione used. During Harry Potter and the Prisoner of Azkaban, Harry and crew were in the Three Broomsticks when a bunch of the professors arrived. Not wanting to be seen, Hermione moved a Christmas tree to block them from view.
The spell Hermione used was Mobiliarbus. Mobilis is Latin for "movable," and arbor means "tree." A little specific, isn’t it? Witches and wizards really do have spells for all occasions.
Homenum Revelio
Homenum Revelio is one of those spells that actually sounds quite useful at first. The intent of the spell is to reveal all humans in the near vicinity. The problem lies in what it doesn’t detect. As in, anything and everything that isn’t human.
Since this is the world of Harry Potter… there are quite a lot of dangerous non-human creatures lurking around. So, it seems rather silly to not have a spell that would instead reveal anything living (and potentially dangerous) within a certain range.
Waddiwasi
Waddiwasi is one of those spells that is very clear in its intended use: it's a prank. Well, it isn’t even really a prank, more of an annoyance. Before we get ahead of ourselves, though, we should probably talk about the spell itself. Waddiwasi is a spell that’ll shoot small and soft wads of…something wherever the caster wants. It’s basically a magical spitball.
There is no practical use for this spell that we can think of. Though it would be very effective at getting the caster into fights, or detention. For what that's worth.
Peskipiksi Pesternomi
So, admittedly, we never actually see this spell used properly... but that may be part of the problem. Lockhart uses Peskipiski Pesternomi during Harry Potter and the Chamber of Secrets in an attempt to ward off a swarm of pesky pixies. It has absolutely no effect.
This could be because Lockhart is incompetent, or it could be because the spell itself is useless. After all, Hermione uses a completely different spell to deal with the pixies. Was he trying to impress the students with a dramatic spell of his own invention? Quite possibly. That sounds very Lockhart, after all.