Optionally, you have a way to kill a creature, or you have a creature card in hand with the mana to cast it that has base power equal to or greater than half its toughness, rounded up.
Steps
Activate Kiki-Jiki by tapping it, creating a token copy of Terror of the Peaks with haste.
When the token Terror of the Peaks enters the battlefield, the nontoken Terror of the Peaks triggers, dealing damage equal to the token Terror of the Peaks' power to the token Terror of the Peaks.
The token Terror of the Peaks dies as a state-based action due to having 0 or less toughness, triggering Kiki-Jiki, untapping Kiki-Jiki.
Repeat.
If you have a way to kill another creature or a creature card in hand, before starting the loop, you may instead create a Terror of the Peaks token, and then kill another creature or cast another creature and kill it using a Terror of the Peaks trigger. This will untap Kiki-Jiki and you may start the loop, giving you an additional Terror of the Peaks trigger each loop, which you can then direct at any target desired.