Activate Phyrexian Altar by sacrificing Grazing Kelpie.
When Grazing Kelpie dies, its persist ability triggers, returning it from your graveyard to the battlefield with a -1/-1 counter on it.
Activate Phyrexian Altar by sacrificing Grazing Kelpie.
When Grazing Kelpie dies, its undying ability triggers, returning it from your graveyard to the battlefield with a +1/+1 counter on it.
Repeat.

Infinite ETB

Infinite LTB

Infinite colored mana

Infinite death triggers

Infinite sacrifice triggers

Mikaeus, the Unhallowed

Phyrexian Altar

Grazing Kelpie

Activate Viscera Seer by sacrificing Grazing Kelpie.
When Grazing Kelpie dies, its persist ability triggers, returning it from your graveyard to the battlefield with a -1/-1 counter on it.
Thran Vigil triggers, putting a +1/+1 counter on Grazing Kelpie.
Resolve the Viscera Seer ability.
Repeat.

Infinite scry 1

Viscera Seer

Thran Vigil

Activate Ashnod's Altar by sacrificing Grazing Kelpie.
When Grazing Kelpie dies, its persist ability triggers, returning it from your graveyard to the battlefield without a -1/-1 counter on it due to Vizier of Remedies.
Repeat.

Infinite colorless mana

Vizier of Remedies

Ashnod's Altar

Activate Zameck Guildmage's first ability by paying {G}{U}, causing each creature you control to enter the battlefield with an additional +1/+1 counter this turn.
Activate Ashnod's Altar by sacrificing Grazing Kelpie, adding {C}{C}.
Grazing Kelpie dies, triggering its persist ability, returning it from your graveyard to the battlefield with no -1/-1 counters due to Zameck Guildmage.
Repeat from step 2.

Zameck Guildmage

Activate Zameck Guildmage's first ability by paying {G}{U}, causing each creature you control to enter the battlefield with an additional +1/+1 counter this turn.
Activate Phyrexian Altar by sacrificing Grazing Kelpie, adding one mana of any color.
Grazing Kelpie dies, triggering its persist ability, returning it from your graveyard to the battlefield with no -1/-1 counters due to Zameck Guildmage.
Repeat from step 2.

Combos with "Grazing Kelpie"