As the sand eroded, a faint sound could be heard whirling under the ground.

Foreboding Statue

{T}: Add one mana of any color. Put an omen counter on Foreboding Statue.
At the beginning of your end step, if there are three or more omen counters on Foreboding Statue, untap it, then transform it.

Were it not for the cultists' fatal curiosity, the terrible machine might have lain dormant for decades more.

Forsaken Thresher

At the beginning of your precombat main phase, add one mana of any color.

Foreboding Statue // Forsaken Thresher

{T}: Add one mana of any color. Put an omen counter on Foreboding Statue.
At the beginning of your end step, if there are three or more omen counters on Foreboding Statue, untap it, then transform it. 

 At the beginning of your precombat main phase, add one mana of any color.

Foreboding Statue // Forsaken Thresher

Artifact Creature — Construct // Artifact Creature — Construct