Suddenly, your creatures gain invulnerability to targeted removal, death via damage, and blockers
Unsurprisingly, this all-time great is the most valuable card from Team Up, and it continues to soar well clear of the competition as the undisputed leader of the entire Sun & Moon era
Proliferating is a very slow way of winning through poison counters, but it still does the job if you dont take your opponent down quick enough
What you want is to keep your opponent's creature alive, and keep smacking it against this to hit to the face
Thats incredibly situational, and most of the time youre actually looking at a weak enchantment that sits around for a few turns doing barely anything
Counter doublers and proliferate also factor in here, beyond just giving you the extra counters youd expect