commands:
A. 1st row
1. replaceitem entity @e[name="Knife"] slot.weapon.mainhand 0 iron_sword
2. effect @e[name="Knife"] invisibility 9999 1 true
3. execute @e[name="Knife"] ^^^2 effect @e[type=!player,type=!mooshroom,type=!armor_stand,r=2] fatal_poison 1 255 true
4. execute @e[name="Knife"] ~~~ detect ~ ~-1 ~ air 0 tp ~~~
5. execute @e[name="Knife"] ~~~ particle minecraft:basic_crit_particle ^-0.5 ^1 ^
B. 2nd row
1. execute @e[name="Iron Nugget"] ~~~ tp ~~~
place comparator and repeater next to the command blocks, and put this command → kill @e[name="Iron Nugget"]
2. execute @p ~~~ summon armor_stand Knife ~ ~-1 ~
3. execute @p ~~~ tp @e[name="Knife",r=1] ^^^1 facing ^^^10
4. playsound item.trident.throw @a
C. last command
1. execute @e[name="Knife"] ~~~ tp ^^^2.5
→ setblock air next to command blocks while time is stopped
→ setblock redstone block next to command blocks when time resumes
credits: / @cxswift1