Its limited to once per turn, so you can point your removal spell at your opponents creatures to make it work on their turns
One recent set introduced not only new double-faced cards, but also a new card type: battles
, Remove three counters from among other artifacts, creatures, and planeswalkers you control: Put an indestructible counter on Tekuthal
Lets look at Poison Dart Frogs text box and break it down line by line
Its enabled by artifacts, and its a huge payoff for playing artifacts later on, and the turns when you play an artifact land and attack with your 8/8 unblockable creature are very strong
His ability to use stun counters on the most important blocker also means he's going to demand a lot of respect on his own, so Blue/Black mid-range strategies may find a lot of use for Kaito