That's a lie. The Freezy symbol goes away, but the creature is till frozen. I've tried it.
My helpful hints:
1. Reverse time cures Poison
2. Reverse creatures that you want after their mutated. (If you mutate/improve a creature into a Purple Nymph 0/4 with dive, reverse it back into your hand and you can play it as a nymph with antimatter.)
3. If you want to play a shield, but you know it will be destroyed (explosion) steal the opponent's shield, wait for it to be destroyed then play your shield.
4. If you have an Otyugh, Ulitharid/ Mind Flayer and a Fallen Elf/Druid and the opponent has a large, dangerous creature, you can use mutation to etiehr kill the creature, make it into something with less attack, or make it into oty food.
5. Don't quit fights, ever. If you are trying to find a rarefarm in t50, fight everyone, because you might win, if not, you know which ones to skip.