Kiki-Jiki, Mirror Breaker + Spark Double

Prerequisites

Spark Double is a copy of Kiki-Jiki.

Steps

1. Activate Kiki-Jiki by tapping it, creating a token copy of Spark Double that has haste. Choose to have Spark Double enter as a copy of Kiki-Jiki.
2. Put the oldest Kiki-Jiki into the graveyard due to the legend rule.
3. Repeat step 1 using the Spark Double token instead.
4. Activate Spark Double by tapping it, creating a token copy of itself with haste that will be sacrificed at the next end step.
5. The Spark Double token enters the battlefield as a nonlegendary copy of Kiki-Jiki with an additional +1/+1 counter.
6. Activate the Spark Double token by tapping it, creating a token copy of itself with haste, exile that token at the end of turn.
7. Repeat from step 2.