Something Dragged Itself From the Water Three Days Early

Описание: I took the lighthouse keeper position because I needed to disappear. Six months alone on a Lake Superior island seemed perfect—automated lighthouse, simple maintenance, complete isolation.
I found the logs on my second day. Journals kept by every lighthouse keeper who'd served here. Standard entries mostly, until every seventh day when the handwriting changed. Shaky. Desperate. And always the same warnings.
The most recent log belonged to Marcus Webb. That's where I found the rules. Eight of them, written in increasingly frantic handwriting: Every seventh day, after dark, something rises from the lake. Don't look at it. Keep every light burning. Walk the island perimeter and place stones at the four cardinal points before sunset. Stay silent. Cover all mirrors. Bar the door. Don't look out windows facing the water. If you hear your own voice calling from outside, don't answer.
Marcus's final entry: "Day seven. I followed all the rules. But I heard my daughter's voice calling from the beach. I know she's dead. But God help me, I want to see her one more time."
The next page was blank. Marcus was listed as "lost at sea." No body found.
I'm on day five now. Day seven is coming.
Last night I woke to something circling the lighthouse. When I checked the rocks this morning, I found wet marks—like something had dragged itself from the lake, circled the tower three times, then returned to the water.
Last night was only day four. It isn't supposed to come until day seven.
An old entry from 1967 said: "It learns. Each cycle, it understands more. The rules that worked before may not work forever."
Tonight is day five. Tomorrow I'll follow Marcus's rules exactly.
But those wet marks appeared three days early.
What did Marcus see when he looked?