How to create a dust particle that deals damage in Minecraft?

I'm in 1.16.5, I have tried for weeks and I just can't get it. The most progress I have ever got is this:

/execute as @e[type=item,nbt={Item:{tag:{ThornPounce:1b}}}] as 1_1COOKIE1_1 at 1_1COOKIE1_1 as @e[type=item,nbt={Item:{tag:{ThornPounce:1b}}}] run summon area_effect_cloud ^ ^1.5 ^2 {Particle:dust,ReapplicationDelay:5,Radius:0.5f,Duration:3,DurationOnUse:3f,Age:x,WaitTime:x,Effects:[{Id:20,Amplifier:1,Duration:20}]}

This command summons an area of effect cloud that looks like the particle and adds an effect to you. I looked into many places and I took a bunch of commands, added them together and tried to edit it to make it how I want it to be.
Can anyone help me?

Solution 1:

I don't know what the first part of your command does:

/execute as @e[type=item,nbt={Item:{tag:{ThornPounce:1b}}}] as 1_1COOKIE1_1 at 1_1COOKIE1_1 as @e[type=item,nbt={Item:{tag:{ThornPounce:1b}}}] run ...

Since your question states that you are just trying to summon an area_effect_cloud, I'm going to ignore it.

Issues with your command

Your area_effect_cloud summon command summons an area_effect_cloud that only exists for 3 ticks. It also doesn't have any color for the dust particle, which is required. It also has x for the Age: and WaitTime, which are invalid values:

summon area_effect_cloud ^ ^1.5 ^2 {Particle:dust,ReapplicationDelay:5,Radius:0.5f,Duration:3,DurationOnUse:3f,Age:x,WaitTime:x,Effects:[{Id:20,Amplifier:1,Duration:20}]}

Working dust cloud

Since I don't know exactly what you are trying to accomplish, I used this command generator to generate the following command:

summon area_effect_cloud ~ ~ ~ {Particle:"dust 0.690 0.561 0.365 1",Radius:0.5f,Duration:1200,Effects:[{Id:20b,Amplifier:1b,Duration:20}]}

How it works

The first part of the command is the /summon command. It is used to spawn entities into the world, like your area effect cloud:

summon area_effect_cloud

The second part of the command specifies the coordinates that the area_effect_cloud should be summoned at. You can use tildes (~) instead of actual numbers to denote relative coordinates, meaning any numbers you put are relative to the execution position (if ran by a player, execution position is at your feet.)

~ ~ ~

So for example, if you wanted to summon it 2 blocks above your feet (right above your head), you could do:

~ ~2 ~

The next part of the command is nested entirely inside a pair of curly brackets ({}). This signifies NBT data, which can specify many attributes about entities. For example, Health, Motion, Position, Rotation, and Age. There are 4 pieces of NBT data that are included on this area_effect_cloud:

Particle
Radius
Duration
Effects

• For this command, the area_effect_cloud is set to use a dust particle, with RGB values of 0.690, 0.561, and 0.365. This gives it a lightish brown color.
• Its radius is also set to 0.5 blocks.
• Its duration is set to 60 seconds (1200 ticks).
• Its Effects are Wither I, for 1 second (20 ticks).