Water - Psychic/Effect 0/0 If this card is in your Graveyard and you control 1 or more continuous "Cubic" Spell/Traps card: You can banish this card from your Graveyard, then target 1 "Cubic" monster in your Graveyard
And here comes the collecting: Gotta cathem all
The most likely reasons are if it's sacrificed, if it's legendary and another legendary permanent with the same name is controlled by the same player, if it's a planeswalker and another planeswalker with the same subtype is controlled by the same player, if it's a creature with toughness 0 or less, or if it's an Aura that's either unattached or attached to something illegal
Successful blink decks have existed in Modern before, thanks largely to Soulherder
In that case the card is not cast and simply remains where it is (which in the case of Omen Machine is the exile zone.) With a card like Wear // Tear, however, the situation is a bit more complex
Some of the comments on TCGPlayer help to explain the price