Seedcradle Witch, Bloom Tender, and Prismwake Merrow

Prerequisites

• Seedcradle Witch on the battlefield
• Bloom Tender on the battlefield
• Prismwake Merrow in hand
• Bloom Tender does not have summoning sickness
• available

Steps

1. Cast Prismwake Merrow by paying
2. Prismwake Merrow enters the battlefield, triggering itself, making a permanent you control all colors until end of turn
3. Activate Bloom Tender by tapping it, adding
4. Activate Seedcradle Witch by paying , giving Bloom Tender +3/+3 until end of turn and untapping it
5. Repeat from step 3

Results

• Infinite black mana
• Infinite blue mana
• Infinitely large Bloom Tender until end of turn
• Infinite red mana