May I perhaps have a few reasons a character would fake their death? It's for a Creepypasta I'm writing.
It did not occur to me that there were people still writing actual Creepypastas and not just fanfiction. But it looks like you're doing both, so more power to you! I hope you have fun!
Thinking most generally to more specifically, the first reason that comes to mind is: new beginnings.
A character may want to start over in such a way that their old self can never be recovered. The death could be used as a symbolic death of who they used to be. They may not want to be the person they were anymore for some reason or another, potentially even because they saw an aspect of themself they may want to "kill."
In another case, a character may be running from something or someone. The character's previous identity would be known to this entity, which could be a problem for them for a variety of reasons including:
Safety
Consequences of previous actions
A new sense of self that does not match with the entity's preconceived notions of your character's existence (this can be a trans allegory, an "I'm not like you, Dad!" story, or a being hunted down by a scary science facility of ill repute and unknown origin story)
Very low bullshit tolerance (“You are NOT getting me into that shit again if you can't find me!”)
Faking one's death just to get away from someone scheming can be played for comedy depending on what aspects you lean into. Is this some idiot with ten thousand get rich quick schemes up their sleeves or someone more than willing to throw someone else under the bus for their own safety/gains?
Third option is they need to be dead. Your character should be dead for some reason but they aren't done living yet. This also has a variety of flavors that can be mixed and matched with previous examples!
There is something they cannot do while "alive"
Something will be stopped with their "death"
Someone very badly wanted them dead, but can be temporarily sated with this "death" so long as your character is careful
And there is also the copout answer of: they never meant to fake their death, they almost died/were nearly killed but got better and now must deal with living as legally dead.
Good luck on your Creepypasta!