Cards Exhausted through effects other than their own will never be saved. Likewise, Ethereal cards will not be saved at the end of a turn when they Exhaust themselves. Deus Ex Machina is Unplayable, and its effect to Exhaust itself when drawn does not count as playing it, so it will not be saved.
Cards played by Havoc and Omniscience temporarily gain the "Exhaust" effect, so the Strange Spoon can save these cards. However, if the card to be played is Unplayable (e.g. Wound, Tactician), it will Exhaust without being played, preventing the Strange Spoon from triggering.
As of version 2.0, Strange Spoon interacts oddly with Omniscience. If the card played by Omniscience is saved by Strange Spoon, it will have the Exhaust effect for the rest of the combat, and will try to Exhaust every time it is played.[1] Havoc does not have this issue.
Although the in-game description claims that saved cards will discard, this is not entirely true. Instead, the card is simply placed in the discard pile as though it did not have the effect to Exhaust itself. This means that discard-related effects (e.g. Hovering Kite) will not trigger when the Strange Spoon prevents a card from Exhausting.
Tips[]
Remember that taking this relic isn't always advantageous.
Some effects (e.g. Dark Embrace, Dead Branch) reward you for Exhausting cards, and won't trigger if the Strange Spoon saves them.
Other cards (e.g. Shiv, Pride) you'll want to Exhaust, rather than having them remain to clutter your deck.
Because Apparition Exhausts when played and is incredibly powerful, it may be worthwhile to invest in buying a Strange Spoon if you have Apparitions, or in taking the Apparitions if you have Strange Spoon already.
Trivia[]
This relic's flavor text references a popular stage magic trick known as spoon bending.
The practice itself was popularized by the magician Uri Geller, and since been associated with psychokinetic or paranormal abilities. It has been referenced in popular culture many time, such as a scene in The Matrix when a young boy bends a spoon to demonstrate the unreality of a computer simulation, and the evolutionary line of the Psychic-type PokémonAbra, Kadabra, and Alakazam, who utilize spoons to amplify their psychokinetic capabilities.
Update History[]
Patch V2.0: The Watcher
Fixed Rebound card not working with Strange Spoon relic.
Weekly Patch 52: Release Date Price Increase
Updated relic asset for Strange Spoon.
Weekly Patch 3: Balance Balance Balance
Strange Spoon affects cards exhausted by Medical Kit and Blue Candle now.
Hovering Kite) will not trigger when the Strange Spoon prevents a card from Exhausting.
Dead Branch) reward you for Exhausting cards, and won't trigger if the Strange Spoon saves them.
Medical Kit and Curses played with 
Blue Candle may be discarded instead of Exhausted.
