Arrow

speeddamage

Speed Scaled Spells

Infestation

A bunch of magical sparks that fly in every direction

Disc Projectile

Summons a sharp disc projectile

Arrow

Summons an arrow

Bouncing Burst

A very bouncy projectile

Energy Sphere

A fast, arcing projectile

Energy Sphere With Timer

A fast, arcing projectile that casts another spell after a timer runs out

Spells whose damage is scaled based on their change in speed.

Spells with tag pointy

Glowing Lance

A magical lance that cuts through soft materials

Holy Lance

A fast-flying, penetrating lance that glows with power

Magic Arrow

A handy magical arrow

Arrow

Summons an arrow

Arrow is a projectile Spell that shoots a physical arrow, inflicting Slice damage. This spell deals friendly fire and can cause damage to you. It is mostly found in the early parts of Noita.

Tips

While Arrow’s Projectile damage is affected by its speed, it lacks any projectile damage to begin with, so be sure to add Damage Plus or other modifiers.
While the arrow can hurt you, it does not have any bouncing or ricocheting properties and will become harmless after hitting something, making it relatively safe to use on its own unless you fire straight up, or its flightpath intersects with you in another way. If you use a trigger spell with Arrow and hit a wall, however, the arrow can very easily hit you so be aware of the risks.
With its -20 spread modifier, this is one of the most accurate spells in Noita, tied with Glowing Lance, and can even be added to a multicast as a sort of improvised Reduce Spread modifier.
Arrow does not add or subtract from the recoil of the wand - rather it sets recoil to 30. It is kind of like Chainsaw for recoil. So long as you place the Arrow after all the recoil-causing spells.
After impacting terrain, the arrow model changes to have Plant Material at the base. By making the arrow fall feather down, such as shooting a ceiling, you can stack the plant material and turn it into soil. Effectively, arrows can create terrain. Plant material turns into soil when it no longer has any air blocks around it.

Speed & Damage

Main article: Damage Scaled By Speed

The Projectile damage dealt by some spells, including Arrow, depends on the speed of their projectile. Specifically, base damage is multiplied by the ratio of its Final Speed and Initial Speed, i.e.:

D a m a g e = \frac{F i n a l S p e e d}{I n i t i a l S p e e d} * B a s e D a m a g e

Since all the projectiles that have this effect naturally slow down over their lifetime, the damage they cause reduces over time. If you modify them such that they speed up instead then damage increases - the effect works both ways. You can increase the ratio, and thus bonus, by reducing the initial speed, increasing the final speed, or ideally both.

Accelerating Shot is ideal for this since it reduces the initial speed, increases speed over the projectile's lifetime, and prevents it from losing speed from moving through the air.
- This modifier provides no acceleration in the first frame of the projectile's life, and so alone it can't save projectiles that spawn with too little initial speed.
- For Bouncing Burst, up to three copies can be used without additional acceleration
  650px/s initial speed × 0.32 × 0.32 × 0.32 = 21px/s, which is above the limit of 5px/s
- For Energy Sphere, up to two copies can be used without additional acceleration
  400px/s initial speed × 0.32 × 0.32 = 41px/s, which is above the limit of 20px/s
Heavy Shot also reduces initial speed while providing a hefty damage boost (which is multiplied by the speed damage).
Rotate Towards Foes is also ideal since it does not change the projectile's speed, only the direction it is moving in.

All the projectiles with this effect also have a minimum velocity below which they die. If you reduce their starting speed too much they may not spawn at all, or only when you point your wand downwards. Gravity or Anti-Gravity are easy fixes for this, providing enough acceleration to avoid early projectile death. The check for low velocity, and the recording of the projectile's Starting Speed, both happen at the end of the first frame of its life, meaning the die on low velocity speed is the lower bound for the bonus. The upper bound is the projectile's Terminal Velocity, which for all those with this effect is 1000px/s.

Since this damage is calculated as a bonus on impact it cannot be absorbed by Spells to Power. You can do it the other way around though, use Spells to Power to add damage from other projectiles to one with speed scaling - the damage absorbed by Spells to Power will be multiplied by the speed bonus at impact.