When paired with cards like Vines of Vastwood and Old-Growth Troll youve got a winning strategy on your hands
Piru, the Volatile With Piru, the Volatile around, you can opt to pay the mana and keep a 7/7 flying and lifelink dragon around, or let it die to deal 7 damage to each nonlegendary creature
You must have gained life before your end step begins
As such, it's very much a product of its own year and something you're probably only picking up if you're trying to complete some sort of collection
Your opponents might not want to waste valuable removal on something that doesnt make mana, but that just allows The Ooze to keep its secrets until the best moment
And then you play Virbank City Gym (PLS 126/135) so they take extra poison damage, and you attach a Muscle Band (XY 121/146) -- and then you have a knock out for 200 damage for only two energy, which is really strong