You mean it turns one permanent into another of random type?
The base concept is pretty clever. Have the upgraded version also named, Wacky Time Machine, since the effect is the same. That also avoids copyright issues.
Instead of changing permanents, permanently, how about changing creatures temporarily? Effects are always in your favor. If on your own creature, it might give them vamperic, adrenaline, heal the creature, etc. If on a enemy, it might freeze them, damage them, Aflatoxin them, etc. All effects last only that turn except damage and healing. Oh, if aflatoxin kills them (if that is one of the possibles) the enemy still gets a malignant cell that works like normal. If a creature already has the trait that Wacky time effect would give it, (including poison, no stacking) or is already fully healed and heal effect is triggered, no effect.