An uninvited guest

Knock-knock, no need to open doors.
Keep your seats warm while i traverse the floors.

I’m your best friend when in need of comfort.
Yet your worst enemy when you drift to slumber.

Eeny, meeny, miny, moe.
The time for games is over.
The time has gained a foe.

My job is the greatest from winter to fall.
My job seems to be the greatest job of them all...

No matter the light or the heavy sleeper,
Please welcome your host for the night;

The Grim Reaper