Sleep Paralysis — ruling 1

If the target creature is an illegal target by the time Sleep Paralysis tries to resolve, the spell doesn't resolve. It won't enter the battlefield, so its ability won't trigger.

Sleep Paralysis : règles, fonctionnement et interactions (MTG)

Sleep Paralysis is one of those cards players keep asking about. Here is, in plain words, what its official text says, the rulings published by Wizards of the Coast, and the combos players actually run.

Official card text

Enchant creature When this Aura enters, tap enchanted creature. Enchanted creature doesn't untap during its controller's untap step.

How it works : Sleep Paralysis

Original English text — Wizards of the Coast / Scryfall

#1July 12, 2019· Wizards of the Coast
If the target creature is an illegal target by the time Sleep Paralysis tries to resolve, the spell doesn't resolve. It won't enter the battlefield, so its ability won't trigger.
No other card is named in this ruling.