Have Brash Taunter dealt damage, cast Gideon's Sacrifice in response targeting Brash Taunter.
Repercussion triggers, dealing damage to Brash Taunter.
Brash Taunter deals damage to target opponent.
Repeat.

Infinite damage

Repercussion

Brash Taunter

Gideon's Sacrifice

Cast Gideon's Sacrifice by paying {W}, causing all damage that would be dealt this turn to you or to permanents you control to be dealt to Crystalline Crawler instead.
Activate Pestilence Demon by paying {B}, dealing 1 damage to each creature and each player.
Gideon's Sacrifice redirects damage to Crawler, which results in at least four +1/+1 counters being placed on it instead due to Vigor.
Activate Crystalline Crawler's first activated ability at least once by removing at least one +1/+1 counter from it, adding at least {B}.
Repeat from step 2.

Infinite +1/+1 counters on Crystalline Crawler

Infinite colored mana

Infinite damage to opponent and each creature your opponents control

Crystalline Crawler

Vigor

Pestilence Demon

Cast Gideon's Sacrifice by paying {W}, causing all damage that would be dealt this turn to you or to permanents you control to be dealt to Crystalline Crawler instead.
Activate Thrashing Wumpus by paying {B}, dealing 1 damage to each creature and each player.
Gideon's Sacrifice redirects damage to Crawler, which results in at least four +1/+1 counters being placed on it instead due to Vigor.
Activate Crystalline Crawler's first activated ability at least once by removing at least one +1/+1 counter from it, adding at least {B}.
Repeat from step 2.

Thrashing Wumpus

Cast Gideon's Sacrifice by paying {W}, causing all damage that would be dealt this turn to you or to permanents you control to be dealt to Crystalline Crawler instead.
Activate Pestilence by paying {B}, dealing 1 damage to each creature and each player.
Gideon's Sacrifice redirects damage to Crawler, which results in at least three +1/+1 counters being placed on it instead due to Vigor.
Activate Crystalline Crawler's first activated ability at least once by removing at least one +1/+1 counter from it, adding at least {B}.
Repeat from step 2.

Near-infinite +1/+1 counters on all other creatures you control

Near-infinite damage

Pestilence

Cast Gideon's Sacrifice by paying {W}, causing all damage that would be dealt this turn to you or to permanents you control to be dealt to Crystalline Crawler instead.
Activate Scourge of Kher Ridges's first ability by paying {1}{R}, dealing 2 damage to each creature without flying.
Gideon's Sacrifice redirects damage to Crawler, which results in at least three +1/+1 counters being placed on it instead due to Vigor.
Activate Crystalline Crawler's first activated ability at least twice by removing at least two +1/+1 counters from it, adding at least {1}{R}.
Repeat from step 2.

Infinite damage to each creature your opponents control

Scourge of Kher Ridges

Cast Gideon's Sacrifice by paying {W}, causing all damage that would be dealt this turn to you or to permanents you control to be dealt to Crystalline Crawler instead.
Activate Ashen Firebeast by paying {1}{R}, dealing 1 damage to each creature without flying.
Gideon's Sacrifice redirects damage to Crawler, which results in at least three +1/+1 counters being placed on it instead due to Vigor.
Activate Crystalline Crawler's first activated ability at least twice by removing at least two +1/+1 counters from it, adding at least {1}{R}.
Repeat from step 2.

Infinite damage to creatures without flying your opponents control

Ashen Firebeast

Cast Gideon's Sacrifice by paying {W}, causing all damage that would be dealt this turn to you or to permanents you control to be dealt to Crystalline Crawler instead.
Activate Pyrohemia by paying {R}, dealing 1 damage to each creature and each player.
Gideon's Sacrifice redirects damage to Crawler, which results in at least three +1/+1 counters being placed on it instead due to Vigor.
Activate Crystalline Crawler's first activated ability at least once by removing a +1/+1 counter from it, adding at least {R}.
Repeat from step 2.

Pyrohemia

Cast Gideon's Sacrifice by paying {W}, causing all damage that would be dealt this turn to you or to permanents you control to be dealt to Crystalline Crawler instead.
Cast Warmonger by paying {3}{R}.
Activate Warmonger by paying {2}, dealing 1 damage to each creature without flying and each player.
Gideon's Sacrifice redirects damage to Crawler, which results in at least four +1/+1 counters being placed on it instead due to Vigor.
Activate Crystalline Crawler's first activated ability at least twice by removing at least two +1/+1 counters from it, adding at least {2}.
Repeat from step 3.

Combos with "Gideon's Sacrifice"