Spells Solve Problems, Not Squares
Most spell misuse at the table is not about picking the wrong spell. It is about picking the right spell for the wrong reason. A player looks at the battle mat, sees a five-foot gap, and burns a resource that was built to reshape the entire encounter. Spell Use Case is the difference between a caster who fills a hole in the grid and one who removes the problem that made the grid matter. The rules already tell you which is which. You just have to read what a spell actually does before deciding what it is for.
Start with the two teleport-adjacent options, because they are the most commonly wasted. Dimension Door is a 4th-tier spell with an instant duration and self range, and it moves you plus one willing creature to a point you can see. That instant self-range teleport changes positioning, not damage output. Spend it to shuffle five feet closer to a target and you have thrown away a strategic tool for a tactical fidget. The correct use is bypassing an obstacle wholesale or escaping a threat that would otherwise end you. Passwall lives in the same trap. It has Close range, lasts 5 rounds, and opens a tunnel of your height in a straight line up to near distance through a barrier you touch. Casting Passwall to improve a firing angle inside a room misses the point entirely. Its value is bypassing obstacles, reaching hidden areas, and turning a sealed environment into information you did not have a minute ago. Both spells answer the question “how do I get past this,” not “how do I get one square better positioned.”
Two more spells fail for a related reason: players ignore that they cost Focus. Magic Circle creates a near-sized cube centered on the caster that stops a named creature type from attacking or casting hostile spells, and it holds only as long as Focus holds. Break Focus and the protection ends immediately, which leaves the caster exactly as exposed as before. That makes Magic Circle a spell for controlled situations. Negotiation, a held position, a moment where you know you will not be jostled. If someone can disrupt the caster, the circle is a liability dressed as a wall. Spidersilk carries the same Focus condition, with duration keyed to Focus rather than a set number of rounds. Casting it simply because it is on the list wastes it. Timed correctly, it forces enemy movement, disrupts their actions, and shortens the fight. The lesson under both is the same: a Focus spell is a commitment, and you should know what the commitment buys before you make it.
Finger Of Death rounds out the group as the clearest case of misapplied thinking. It has Close range and instant duration, and it kills a creature of level 9 or less outright. Read as a damage spell, it looks like an expensive way to remove some hit points. Read correctly, it is a scalpel. The target is not the enemy with the biggest health bar. The target is the one creature whose removal collapses the encounter: the summoner, the commander, the thing keeping the others coordinated. You are not reducing a total, you are deleting a variable.
The through-line across all five is discipline about purpose. Dimension Door and Passwall bypass. Magic Circle and Spidersilk require Focus and therefore require a plan. Finger Of Death decides. None of them exist to nudge a miniature one square. When a player asks what a spell is for, the honest answer is written in its range, duration, and effect, and it almost never says “grid optimization.”
Running it: Before any spell is cast, ask the player what problem it solves; if the answer is “I move a little,” make them read the entry again.