Myr Welder, Seedcradle Witch, and Prismatic Geoscope

Prerequisites

• Myr Welder on the battlefield
• Seedcradle Witch on the battlefield
• Prismatic Geoscope in exile

Steps

1. Activate Myr Welder using Prismatic Geoscope's ability by tapping it, adding at least Activate Seedcradle Witch by paying , untapping Myr Welder and giving it +3/+3 until end of turn
2. Repeat

Results

• Infinite colored mana
• Infinite untap of creatures you control
• Infinite mana creatures you control can produce
• Infinitely large creature until end of turn