Chains of Mephistopheles, Dredger's Insight, Marina Vendrell's Grimoire, and Grave-Shell Scarab

Prerequisites

• Chains of Mephistopheles on the battlefield
• Dredger's Insight on the battlefield
• Marina Vendrell's Grimoire on the battlefield
• Grave-Shell Scarab in hand
• available

Steps

1. Attempt to draw a card
2. The draw will be replaced by Chains of Mephistopheles, instead causing you to discard Grave-Shell Scarab
3. Then, the draw will be replaced by Grave-Shell Scarab's dredge ability, causing you to mill cards and return Grave-Shell Scarab from your graveyard to your hand
4. Dredger's Insight's first ability triggers, causing you to gain 1 life
5. Marina Vendrell's Grimoire triggers, attempting to draw a card
6. Repeat from step 2

Results

• Infinite self-mill
• Near-infinite lifegain
• Near-infinite lifegain triggers
• Near-infinite self-discard triggers