Nuance abounds nowadays; whereas it was commonplace to mentally coalesce opposing counters on a permanent, I imagine doing so is incorrect.
Suppose one Sengir Vampire has amassed five +1/+1 counters from having sent five creatures to the graveyard, and it is now blocking a Regeneration-enchanted Putrefax, a 5/3 whose infectious damage is dealt in the form of -1/-1 counters. Does Sengir Vampire have zero counters, or ten counters?
Rabid Wombat, green 0/1, which gains +2/+2 for each enchantment on it, enchanted with Unstable Mutation, which gives it +3/+3, and gives it a -1/-1 counter during controller's upkeep. Is this accurate?
0/1. Rabid Wombat cast.
5/6. RW+Unstable Mutation. 3/4 + a 2/2 counter
4/5. 3/4 + a 2/2 counter + -1/-1 counter
3/4. 3/4 + a 2/2 counter + (2 x -1/-1 counters) no cancellation here?
2/3. 3/4 + a 2/2 counter + (3 x -1/-1 counters) ...
.. etc. correct?
Rock Hydra comes into play with casting-time X +1/+1 counters, and receives damage in the form of loss of the counters. If it becomes infected by Putrefax, which deals damage as -1/-1 counters, is the infection essentially redundant to Rock Hydra's normal life cycle? Or does the state-based action's removal of the counter count as damage which then removes another head?
Is reduction of a creature's toughness due to counter-based actions considered damage?