Gerrit, Old but Wise

Whenever you cast an instant, you may discard a
card. If you do, that instant gains experiment and
can't be countered.
Whenever you would flip a coin for an
experiment ability, role a d20 instead. Numbers
1-6 count as a loss, 7-20 as a win. If the result is
18 or higher, copy the spell twice instead of once.
Exile an instant from your graveyard: Gerrit, Old
Mage gains hexproof until end of turn.