Cast Body of Research by paying ({G} magic symbol) ({G} magic symbol) ({G} magic symbol) ({U} magic symbol) ({U} magic symbol) ({U} magic symbol) , creating a 0/0 Fractal creature token, and then putting a number of +1/+1 counters on it equal to your deck size.
Activate Altar of Dementia by sacrificing the Fractal, causing target player to mill cards equal to the Fractal's power.