The check for ten or more point counters happens only as the last ability is resolving
It was honestly hard to pick just one uncommon from this set, as I have a lot of time for Nowhere to Run and Untimely Malfunction as well
Credit: Wizards of the Coast Credit: Wizards of the Coast Gwen Stacy / Ghost-Spider Saffgor: This synergizes extremely well with the Proliferate stuff from Jeskai's precon in Edge of Eternities, given that second ability on Ghost-Spider doesn't specify +1/+1 counters
This three-drop Green rare enchantment will play us out
Alternatively, you can add some more variety to the creatures in this deck, with cards like Gladiolus Amicitia and Tannuk, Memorial Ensign both giving an added dimension to the deck , and, as legendary creatures, you only need to add one or two copies so you wouldn't need to readjust your mana, bar maybe including one or two extra mountains in place of forests.