Serpentine Curve seems really potent in a deck that runs plenty of instant and sorcery cards. Gotta like it counts both you own in exile and in your graveyard.
1. Play Cosmic Intervention during your turn.
2. Sac Flooded Strand.
3. Flooded Strand returns at the beginning next end step.
4. Sac the Flooded Strand at the end step.
5. Flooded Strand should then return at the beginning of the next end step of the next turn.
6. Sac Flooded Strand.
I can see Foretell used with cards that can produce mana on the spot. Dark Petition, Inner Fire and Gilded Lotus as examples. They become free once mana is paid back.
If only this Demon was Legendary to be a Commander for B decks.
1. Play Cosmic Intervention during your turn.
2. Sac Flooded Strand.
3. Flooded Strand returns at the beginning next end step.
4. Sac the Flooded Strand at the end step.
5. Flooded Strand should then return at the beginning of the next end step of the next turn.
6. Sac Flooded Strand.
If only this Demon was Legendary to be a Commander for B decks.