Legal Discovery

When Discovery enters the battlefield or a
Lawsuit permanent is destroyed, exile the top
card of each player's library.
During each player's turn, that player may play
lands or cast spells from among cards exiled with
Discovery, and they may spend mana as though
it were mana of any color to cast that spell. When
they do, exile the top card of their library.
If there are no other Legal permanents on the battlefield sacrifice Discovery.