On use, throws up to 5 spaghetti ropes towards nearby enemies and captures them, petrifying them for 4 seconds.
When the petrification ends, the spaghetti will be pulled out and enemies will gain a glitchy yellow-red effect surrounding them as they become permanently glitched, making them occasionally and randomly lose their AI and lose 2 HP per second during the effect.
When an enemies loses their AI — indicated by the enemy becoming transparent — they can have their movement and attack patterns become broken or disrupted, take drastically increased knock-back and slide around the room, and occasionally leave brown slippery creep on the ground behind them.
Notes
Nil Pasta's ropes have a fixed initial reach of ~500 pixels, but can stretch infinitely once an enemy is caught.
If there is no enemies in the room, the spaghetti ropes will lash out in random directions when Nil Pasta is used.
Enemies caught by Nil Pasta's ropes cannot be released by using the item again.
Bosses can be affected by Nil Pasta, making their attack patterns become occasionally disrupted and unpredictable.
Mother is the only boss that is immune to Nil Pasta's effect.
The way that Nil Pasta makes enemies "glitched" is by applying Poople's own AI code to them.
This is indicated by how an enemy under the effect creates brown slippery creep, and can shoot poop projectiles and spawn Brownie Corn when sliding into an obstacle or wall fast enough.
Book of Virtues: No special interaction; creates a default wisp.
Abyss: Absorbing Spaghetti Code creates a yellow-red Abyss Locust that has a 3.33% chance for an enemy that takes damage from the locust to become glitched.
Video Showcase
Trivia
Nil Pasta's name is a play on words of the "Nil passed to reference" error in LUA, the main programming language used by mods in The Binding of Isaac: Afterbirth+ and Repentance — The words "nil passed to" sound similar to "nil pasta".
Nil Pasta's flavor text, "spaghetti code", is a pejorative phrase for unstructured and difficult-to-maintain but otherwise mostly stable source code, referencing Nil Pasta's effect on enemies.
The glitched status effect using Poople's AI is based on a error during development that could happen due to how Fiend Folio's enemy's IDs are structured, where the AI of enemies that all had the same ID would default to variant 0. Erfly, the creator of the item Nil Pasta, has all their enemies they coded for the MOD under the same ID but all with different variants, with Poople having the variant ID of 0. Thus, when the error occurred, it caused all of those enemies under the same ID to gain Poople's behavior.
It could also deliberately be a reference to a common bug caused by "download errors" in Fiend Folio and other similar mods, where enemies stay frozen and are unable to act, sliding around at the slightest bit of knockback ― similar to how Poople has slippery movement and reduced knockback resistance.
Mother is the only boss that is immune to Nil Pasta's effect.
Poople's own AI code to them.
Brownie Corn when sliding into an obstacle or wall fast enough.
Car Battery / 
Eternal Car Battery: Multiplies the amount of ropes and enemies that can be captured.
Book of Virtues: No special interaction; creates a default wisp.
Abyss: Absorbing Spaghetti Code creates a yellow-red Abyss Locust that has a 3.33% chance for an enemy that takes damage from the locust to become glitched.
