Looking to establish an evil horror cult? The first thing you will need is a good graphics department. It used to be that a trusty pentangle or inverted crucifix would do the trick, but in our branding-conscious age, horror movies must try harder. It seems no modern-day chiller is complete without its bespoke symbol, usually signifying an ancient secret society or some other form of unspeakable, but easily drawable, evil. Something that would look good on a T-shirt.

Recent history is garlanded with examples: The Blair Witch Project’s “stick man”; the similar design in Ben Wheatley’s Kill List. Sinister gave us the “Bughuul” symbol; Devil’s Due the Antichrist gateway; and 13 Ghosts a selection of “Black Zodiac” signs. This week, we’ve got Brightburn. This fusion of Superman and The Omen centres on a strangely powerful boy-who-fell-to-Earth called Brandon. He creates his own logo: a double diamond based on his initials. He’s so proud of it that he scribbles it in notebooks, on windows and at the scene of his crimes.

We will soon have more glyphs to glean in Midsommar, Ari Aster’s much-anticipated follow-up to Hereditary. Hereditary was already a classic example of what we might call “logo horror”. It made liberal use of a curlicued symbol that resembled an ornate wall-mounted coat-rack but was actually “the sigil of Paimon” – what else? – signifying demonic cult membership. Aster is at it again with Midsommar. Set in sunny Sweden, it looks like a Wicker Man-style jaunt into folk horror. Its chief symbol, a triangle with circles at its bottom corners, will be familiar to actual Swedes: it is a pagan fertility symbol, often found atop maypoles (not to be confused with the Deathly Hallows from Harry Potter). And Midsommar’s trailers are chock-full of other mysterious runes and symbols, some Norse-looking, others possibly made up. Fans are already poring over the images.

This could be a dangerous avenue to head down: where rather than being stories to move us, movies become puzzles to solve. We have already had a warning this year: Under the Silver Lake, from the director of It Follows, in which a symbol sent Andrew Garfield on a mystical goose chase. Audiences had no inclination to follow. It is fine to add a deeper layer of symbolic meaning – as Hereditary and many other movies do. But when the symbolism becomes literal and overbearing, you risk going too far down the rabbit hole. Before you know it, you could be mainlining podcasts about “Illuminati symbolism at the Met Gala” or buying brain pills on Infowars. When you’re a hammer, everything looks like a nail; when you’re a conspiracy theorist, every triangle, circle and squiggle looks like evidence of a secret masterplan (that would also make a cool T-shirt).

Brightburn is in UK cinemas from Wednesday 19 June