Carrion Feeder is in your graveyard, you must have ({3} magic symbol) available and three removable counters from creatures you control, ensuring to leave a +1/+1 counter on
Cryptic Trilobite and
Basking Broodscale.
If
Carrion Feeder is in your hand, you must have enough mana to cast it.
Steps
Cast
Carrion Feeder by paying its mana cost if it is in your hand. Otherwise, activate
Tayam by paying ({3} magic symbol) and removing three counters from creatures you control, causing you to mill three cards and return
Carrion Feeder from your graveyard to the battlefield with a vigilance counter on it.
When
Carrion Feeder enters the battlefield,
Metastatic Evangel triggers, causing you to put a +1/+1 counter on
Cryptic Trilobite and
Basking Broodscale and a vigilance counter on
Carrion Feeder.
Basking Broodscale triggers, creating a 0/1 Eldrazi Spawn creature token that enters with a vigilance counter on it.
Activate
Cryptic Trilobite by removing a +1/+1 counter from it, adding ({C} magic symbol) ({C} magic symbol) that can only be spent to activate abilities.
Activate the Eldrazi Spawn by sacrificing it, adding ({C} magic symbol) .
Activate
Tayam by paying ({3} magic symbol) , removing both vigilance counters from
Carrion Feeder and another counter from a creature you control.
Holding priority, activate
Carrion Feeder by sacrificing it.
Resolve the
Tayam ability, causing you to mill three cards and return
Carrion Feeder from your graveyard to the battlefield with a vigilance counter on it.
Repeat from step 2.
Repeat.
Notes
If you do not control any other creatures, you may instead activate
Tayam before sacrificing the Eldrazi Spawn, thus using the Eldrazi Spawn's vigilance counter as the third counter for activation. Doing this will add ({1} magic symbol) to the mana needed for the combo.