Infinite green mana, Infinitely large creature until end of turn
During your combat phase, activate Necrotic Ooze using Kjeldoran Elite Guard's ability by tapping it, giving it +2/+2 until end of turn.
Activate Necrotic Ooze using Devoted Druid's second ability by putting a -1/-1 counter on it, untapping it.
Repeat.
Once Necrotic Ooze has infinite toughness, you may instead use Devoted Druid's first ability to get infinite green mana.
Component Cards
How It Works
During your combat phase, activate Necrotic Ooze using Kjeldoran Elite Guard's ability by tapping it, giving it +2/+2 until end of turn.
Activate Necrotic Ooze using Devoted Druid's second ability by putting a -1/-1 counter on it, untapping it.
Repeat.
Once Necrotic Ooze has infinite toughness, you may instead use Devoted Druid's first ability to get infinite green mana.