Chains of Mephistopheles, Dredger's Insight, Marina Vendrell's Grimoire, and Stinkweed Imp

Prerequisites

• Chains of Mephistopheles on the battlefield
• Dredger's Insight on the battlefield
• Marina Vendrell's Grimoire on the battlefield
• Stinkweed Imp 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 Stinkweed Imp
3. Then, the draw will be replaced by Stinkweed Imp's dredge ability, causing you to mill cards and return Stinkweed Imp 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