This is especially popular for powered cubes, vintage cubes, dual lands, reserve list staples, and highly optimized Commander environments where replacement costs can become extremely high
To use them in battles, you had to have the associated Fossil Item card, but the mechanics are no longer relevant in modern day play
As with Elizabeth Rices Temur Cube
I started out with every Nicol Bolas, searched for every card with Bolas in the title, expanded the search to Nicol Bolas quoted in flavor text, and finally checked all the various cards that depict various Nicol Bolas-related things
The Moment's last ability will destroy itself before you can sacrifice it if there are two or more time counters on it as its last ability resolves
They Meld into a Creature which probably also makes your opponents sad