There are at least three additional counters of any kind on
Tayam and/or additional creatures you control.
Mana Needed
({3} magic symbol) ({R} magic symbol) available.
Steps
Activate
Phyrexian Altar by sacrificing
Grim Initiate, adding mana.
When
Grim Initiate dies, it triggers, creating a 0/0 creature token with a +1/+1 counter on it as well as a vigilance counter due to
Tayam.
Activate [[
Tayam]] by paying ({3} magic symbol) and removing three counters from creatures you control, milling three cards and returning
Grim Initiate from your graveyard to the battlefield with a vigilance counter on it.
Declare that you are activating
Tayam's ability again, so state-based actions will not be checked until the ability is activated.
While paying that ability's cost, activate the creature token using the
Wall of Roots mana ability from
Agatha's Soul Cauldron by putting a -0/-1 counter on it, adding ({G} magic symbol) .
Complete the activation by paying ({3} magic symbol) and removing a vigilance counter and a -0/-1 counter from the creature token and a vigilance counter from
Grim Initiate.
Holding priority, activate
Phyrexian Altar twice by sacrificing
Grim Initiate and the creature token, adding mana.
When
Grim Initiate dies, it triggers, creating a 0/0 creature token with a +1/+1 counter on it as well as a vigilance counter due to
Tayam.
Resolve
Tayam's ability, milling three cards and returning
Grim Initiate from your graveyard to the battlefield with a vigilance counter on it.
Repeat from step 4.
Notes
This order of operations (and the additional ({2} magic symbol) starting mana) are necessary because you must activate mana abilities before paying costs, and so you cannot use Ashnod's Altar to get mana from the creature you need to remove counters from.
Results
Infinite creature ETB.
Infinite creature LTB.
Infinite creature sacrifice triggers.
Infinite death triggers.
Infinite self-mill.
Metadata
In 0 decks according to EDHREC.
Bracket Tag
This combo has been estimated to be Exhibition (Bracket 1+).