Genesis 6:1-4
Four verses of terse Hebrew, two rare construct phrases, one verb shared with Eden, and three millennia of interpretation. Genesis 6:1-4 is the OT-side anchor of the Watchers tradition — but before any expansion, the text has its own grammar to declare.
Genesis 1 uses לְמִינוֹ (after their kind) ten times for plants, sea creatures, birds, and land animals — then drops the formula entirely and replaces it with בְּצֶלֶם אֱלֹהִים. Humans are not animals; angels are not in the image; and Genesis 6 is the violation that proves both rules.