Svella, Ice Shaper, Roxanne, Starfall Savant, Agatha of the Vile Cauldron, and Umbral Mantle

Prerequisites

• Svella, Ice Shaper on the battlefield
• Roxanne, Starfall Savant on the battlefield
• Agatha of the Vile Cauldron on the battlefield
• Umbral Mantle on the battlefield
• available

Steps

1. Activate Svella's first ability by paying and tapping it, creating a Icy Manalith token
2. Activate the Icy Manalith token by tapping it, adding
3. Roxanne's second ability triggers, adding
4. Activate Svella by paying and untapping it, giving it +2/+2 until end of turn
5. Repeat

Results

• Infinitely large creature until end of turn
• Infinite tapped Icy Manalith tokens