Put a +1/+1 counter on a creature you control.
Moss-Pit Skeleton triggers, putting itself on top of your library.
Chalk Outline and Insidious Roots trigger.
Resolve the Chalk Outline trigger, creating a 2/2 Detective creature token and a Clue token.
When the Detective enters the battlefield, Snarling Gorehound triggers, causing you to surveil 1, putting Moss-Pit Skeleton into your graveyard from the top of your library.
Resolve the Insidious Roots trigger, creating a 0/1 Plant creature token, then putting a +1/+1 counter on each Plant you control.
Moss-Pit Skeleton and Snarling Gorehound trigger.
Resolve the Snarling Gorehound trigger, causing you to surveil 1.
Resolve the Moss-Pit Skeleton trigger, putting it on top of your library.
Repeat from step 3.

Infinite +1/+1 counters on certain creatures

Infinite Clue tokens

Infinite creature tokens

Infinite ETB

Infinite surveil

Snarling Gorehound

Insidious Roots

Chalk Outline

Moss-Pit Skeleton

Put a +1/+1 counter on a creature you control.
Moss-Pit Skeleton triggers, putting itself on top of your library.
Tormod and Insidious Roots trigger.
Resolve the Tormod trigger, creating a 2/2 Zombie creature token.
When the Zombie enters the battlefield, Snarling Gorehound triggers, causing you to surveil 1, putting Moss-Pit Skeleton into your graveyard from the top of your library.
Resolve the Insidious Roots trigger, creating a 0/1 Plant creature token, then putting a +1/+1 counter on each Plant you control.
Moss-Pit Skeleton and Snarling Gorehound trigger.
Resolve the Snarling Gorehound trigger, causing you to surveil 1.
Resolve the Moss-Pit Skeleton trigger, putting it on top of your library.
Repeat from step 3.

Tormod, the Desecrator

Put a +1/+1 counter on a creature you control.
Moss-Pit Skeleton triggers, putting itself on top of your library.
Desecrated Tomb and Insidious Roots trigger.
Resolve the Desecrated Tomb trigger, creating a 1/1 Bat creature token.
When the Bat enters the battlefield, Snarling Gorehound triggers, causing you to surveil 1, putting Moss-Pit Skeleton into your graveyard from the top of your library.
Resolve the Insidious Roots trigger, creating a 0/1 Plant creature token, then putting a +1/+1 counter on each Plant you control.
Moss-Pit Skeleton and Snarling Gorehound trigger.
Resolve the Snarling Gorehound trigger, causing you to surveil 1.
Resolve the Moss-Pit Skeleton trigger, putting it on top of your library.
Repeat from step 3.

Desecrated Tomb

Put a +1/+1 counter on a creature you control.
Moss-Pit Skeleton triggers, putting itself on top of your library.
Skeleton Crew and Insidious Roots trigger.
Resolve the Skeleton Crew trigger, creating a 2/2 Skeleton Pirate creature token.
When the Skeleton Pirate enters the battlefield, Snarling Gorehound triggers, causing you to surveil 1, putting Moss-Pit Skeleton into your graveyard from the top of your library.
Resolve the Insidious Roots trigger, creating a 0/1 Plant creature token, then putting a +1/+1 counter on each Plant you control.
Moss-Pit Skeleton and Snarling Gorehound trigger.
Resolve the Snarling Gorehound trigger, causing you to surveil 1.
Resolve the Moss-Pit Skeleton trigger, putting it on top of your library.
Repeat from step 3.

Combos with "Snarling Gorehound"