It is not an EX card, so you do not have to worry about your opponent gaining two points when it is defeated
If Explorer's Cache isn't on the battlefield as its activated ability resolves, you can't remove a +1/+1 counter from it, so you won't put a +1/+1 counter on the target creature
I left very happy and would give my highest recommendation if you have old collectibles to sell
TOURNAMENT POLICIES Proof of Match Result : It is recommended that players take a screenshot of the victory screen for each game
They are Vrondiss, Rage of Ancients (a Dragonborn Barbarian, leading the red/green Draconic Rage deck), Prosper, Tome-Bound (a Tiefling Warlock, helming the red/black Planar Portal deck), Sefris of the Hidden Ways (a Genasi Wizard, leading the White/Blue/Black Dungeons of Death deck), and, finally, Galea, Kindler of Hope (a Half-Elf Paladin, topping the White/Blue/Green Aura of Courage deck)
On Paper Shortly after rotation, most of the popular cards in Standard would have already started to see their value go down