Whenever Xolatoyac enters or attacks, put a flood counter on target land. That land is an Island in addition to its other types for as long as it has a flood counter on it.
At the beginning of your end step, untap each permanent you control with a counter on it.
Xolatoyac is a Simici counters-and-lands toolbox that floods opposing or your own lands into Islands while quietly building a counter-based engine. Each turn you grow creatures and lands with counters, swing for chip damage with islandwalk synergies, and use the end-step untap to double up on mana, attackers, or activated abilities. You win by snowballing big counter creatures or assembling an untap-fueled mana/combo turn.
Free, repeatable counter generation every combat that fuels proliferate and counters-matter payoffs
End-step untap effectively gives pseudo-vigilance and extra mana from any permanent carrying a counter
Turns your own lands into Islands to enable islandwalk evasion across the table
Simici gives access to the format's best ramp, card draw, and proliferate engines
Flexible: the flood counter can hose opposing lands or supercharge your own
At 6 mana the commander is slow and does nothing the turn it lands beyond a single counter
No built-in evasion or protection on the body itself, so it's easy to remove repeatedly
The untap triggers only on your end step, limiting explosive same-turn combos
Heavily reliant on having counters in play to make the untap clause matter
Vulnerable to counter-removal and graveyard/land hate in lands-matter builds
Cloning evasive or counter creatures stretches the snowball and abuses the islandwalk you create.
Lean into a single axis—either tight +1/+1 counters with multipliers (Hardened Scales, Branching Evolution) and proliferate (Flux Channeler, Evolution Sage), or a lands-matter ramp shell (Cultivate, The Gitrog Monster, Tireless Tracker) that exploits the untap clause for mana. Add protection like Heroic Intervention and Lightning Greaves so your 6-drop sticks, and trim cute cards for proven payoffs and faster ramp to cover the slow start. For higher power, build toward a deterministic untap loop or proliferate-driven mana engine that lets you cast an X-finisher in a single turn.