Fleet Swallower + Fraying Sanity

Fleet Swallower

Fraying Sanity

How it works

1. Declare Fleet Swallower as an attacker.
2. Fleet Swallower triggers, causing the opponent enchanted by Fraying Sanity to mill cards equal to half their library size, rounded up.
3. At the beginning of your end step, Fraying Sanity triggers, causing the opponent to mill cards equal to the number of cards put into their graveyard this turn.