Devoted Druid, Twinning Staff, Ivy, Gleeful Spellthief, Lion Umbra, and Banishing Knack

Prerequisites

• Devoted Druid on the battlefield
• Twinning Staff on the battlefield
• Ivy, Gleeful Spellthief on the battlefield
• Lion Umbra in hand
• Banishing Knack in hand
• available

Steps

1. Cast Banishing Knack by paying , targeting Devoted Druid
2. Ivy triggers
3. Choose not to copy Banishing Knack Resolve Banishing Knack Cast Lion Umbra by paying , targeting Devoted Druid
4. Ivy triggers, copying Lion Umbra twice due to Twinning Staff
5. Choose to have one copy target Ivy and the other copy target Devoted Druid
6. Resolve all three Lion Umbras, attaching one to Ivy if it's modified and two to Devoted Druid
7. Activate Devoted Druid using the ability given to it by Banishing Knack by tapping it, returning the nontoken Lion Umbra from the battlefield to your hand
8. Activate Devoted Druid's second ability by putting a -1/-1 counter on it, untapping it
9. Activate Devoted Druid's first ability by tapping it, adding
10. Repeat steps 8 and 9 one additional time, then repeat step 8 one additional time
11. Repeat from step 4

Results

• Infinite power and toughness for certain creatures
• Infinite storm count