Raycasting example

run in a loop:

execute as @a[scores={click=1..}] at @s run summon minecraft:armor_stand ^ ^ ^2 {Invisible:1,Invulnerable:1,NoGravity:1,Tags:["ray"]}
scoreboard players reset @a[scores={click=1..}] click

execute as @e[tag=ray,tag=!rotated] at @s run tp @s ~ ~ ~ facing entity @p
tag @e[tag=ray] add rotated

execute as @e[tag=ray] at @s run tp @s ^ ^ ^-0.5
execute as @e[tag=ray] at @s run particle minecraft:cloud ~ ~ ~ 0.05 0.05 0.05 0.05 20
execute as @e[tag=ray] at @s unless block ~ ~ ~ air run kill @s

scoreboard players add @e[tag=ray] timer 1
kill @e[tag=ray,scores={timer=100}]