When human corpses are in short supply, stitchers get creative.

Drownyard Amalgam

When Drownyard Amalgam enters the battlefield, target player mills three cards. (They put the top three cards of their library into their graveyard.)
{2}{U}: Drownyard Amalgam can't be blocked this turn.

When this creature enters, target player mills three cards. (They put the top three cards of their library into their graveyard.)
{2}{U}: This creature can't be blocked this turn.