a theoretical deck i came up with they may or may not allow for infinite +1/+1 counters.
conclave mentor and essence symbiote come out 1st ready to have abilities activated
wildwood scourge is played for as high an X value that can be afforded.
Mentor's ability triggers.
mutate into vulpikeet. mutate ability triggers adding +1/+1 (mentor's ability triggers making it +2/+2)
because scourge is now a 'fox bird' not 'hydra', its ability triggers on itself (mentor's ability triggers meaning another +2/+2)
essence symbiote ability triggers (mentor's ability triggers again for +2/+2)
symbiote's counters cause Scourge's ability to trigger for another +2+2 (because mentor)
and because scourge is no longer a hydra, everytime any number of +1/+1 counters is put into it, it puts another 1 as a separate instance, which should constantly loop to infinity
the Conclave mentor & invigorating surge may not even be necessary. in which case they can be replaced with tutoring or mana fixing cards. Something like pridemalkin, garruk's uprising or gemrazer to add trample, so even being blocked isn't a problem.
EDIT: i changed some cards around, added Ozolith so that IF the hydra is destroyed, the ozolith can store the inifite counters & pass them onto another creature.
i was hoping there would be a card that gained life every time a counter is added, but that isn't a thing.
