Zimone's Hypothesis 
Instant
You may put a +1/+1 counter on a creature. Then choose odd or even. Return each creature with power of the chosen quality to its owner's hand. (Zero is even.)
Legality
standardNOT LEGALpioneerNOT LEGALmodernNOT LEGALlegacyLEGALvintageLEGALcommanderLEGAL