How should you visually describe in a comic a spell cast in a subtle and stealthy manner? In Star Wars, Jedi sometimes use jedi mind trick, but it's hard to tell for some people from a drawn image that a telepathic signal is sent to the victim. Is there a way to visually tell in an obvious way that such a stealthy and subtle spell was cast while not wasting several panels just to explain it? I am trying to think of the best way. I was thinking hand signals, but you waste several panels to do that, I was also thinking magic runes, but it's not subtle, and I was thinking latin words being chanted, but it's not subtle either.
I'd do a call out: The spell is cast by a subtle gesture, which you might not see in the "big picture", but circle the oddly held hand, perhaps with a ring on it: the ring glows with a magic light. Draw a line to the next panel and show this close-up. Next panel, back to the big picture, but the spell is cast, the victim shows it in their expression.
So I'm going to the D&D system of magic which requires three components: Somatic (a gesture or motion, ala the handwave in the Jedi mind trick/ Spell Circles in "The Owl House"/Martial Arts Movements for Bending in Avatar), material (a physical object that is usually consumed by the spell on activation and may have a relation to an effect... a feather might be used in magical flight or a carrot or apple consumed in a spell that summons a magical steed. Think the Glyphs Spells in "The Owl House" which consume whatever they are drawn on when activated), and vocal (using a magic word to activate the spell. It's pronounced "LEVI-o-sa!" May take the form of of a single word or two (Harry Potter) a rhyme (Sabrina the Teenage Witch, The Fey in "Gargoyles"), or a chant or statement in another language (Latin/Hebrew/Other ancient Languages for human magic in "Gargoyles", Chinese/Japanese in "Jackie Chan Adventures", backwards spelling in DC comics). Occasionally this also will only affect those who hear the spell cast).
D&D spells would typically require at least one of these for all magic, and often all three. Thus if a character was bound, they could not cast magic with somatic components... and if they were gagged they couldn't cast magic with vocal components either. But you could also take feats to work around this (certain classes got these feats for free too. Sorcerers in certain editions never needed material componants (at least those with out a fixed price) and certain feats allowed casters to create a version of a spell that didn't require a component at the cost of making the spell more difficult to cast).
One of the better depictions I've seen of combining is a Kamen Rider transformation (Kamen Rider Wizard often works the best, both because of his more magical than most nature and the fact that he does other "spells"), but almost every Kamen Rider includes a trinket that is moved through a fluid motion, touched to a special belt (called a Driver) while shouting "Henshin" and a follow up posing is done to complete a transformation (Thus creating a somatic, vocal, and material aspect to the change). Wizard, puts a specific ring on his left hand, touches it to a hand symbol on his belt, shouts Henshin, and strikes a pose and is transformed. To activate other powers, he needs to use other rings which have fewer requirements (usually touch the driver and strike the pose).
One way to be subtle is to focus on the material componant by having the spell contained in a one off object that is activated by waving that item in a simple motion, consuming the object. These material componants could be "playing cards" with glyphs or runes on them. A way to do hand motions is to draw the hand in the begining and ending motion (Or at every point of change) in a single panel with an arrow showing the the steps the motion goes through. If each spell has a unique jesture, you can do it subtlety by showing the arrow pattern with the hand in the start motion on one panel and finish up on the next panel with the hand in the end position and the spell taking effect (look at Harry Potter Video Games or the Wand spots where you can use your wand in the Harry Potter sections in Universal Studios Parks to see how they have a motion to activate a special magical effect built into the park's theming).
A vocal component need not be loud and most users of this trope do eventually get to a point where they don't always say the vocal component to get the thing to happen (Harry Potter does have advanced lessons that teach how to do magic voiceless, and it seems that the more powerful the spell's effect the more difficult it is to be voiceless... to the point that Dumbledore's display of impressive magic without use of a vocalization is proof of his power and skill.).