Activate Kiki-Jiki by tapping it, creating a token copy of Hostage Taker.
When the Hostage Taker token enters the battlefield, it triggers, exiling Kiki-Jiki until Hostage Taker leaves the battlefield.
Activate Umbral Collar Zealot by sacrificing the Hostage Taker token.
When the Hostage Taker token dies, Kiki-Jiki is returned from exile to the battlefield.
Resolve the Umbral Collar Zealot ability.
Repeat.
This clever loop relies on Kiki-Jiki, Mirror Breaker continually spawning a temporary copy of Hostage Taker to temporarily exile the goblin legend itself. While the original Hostage Taker isn't in play to do this, every time you sacrifice the token copy to Umbral Collar Zealot's ability, Kiki-Jiki is freed from exile to repeat the process. The Zealot's passive surveil 1 also triggers with each sacrifice, letting you sculpt your draws infinitely as you churn through all those leaves-the-battlefield and death triggers.