With it's incredible bulk Gliscor could eat most hits from full and easily heal it off with Poison Heal. Though most ran physical defense, it could also run mixed bulk to eat an Ice Beam from Slowkings trying to catch it off guard. Rillaboom's Grassy Terrain only meant it had to switch to using High Horse Power over Earthquake, and nearly nothing could deal with the combination of Ground stab and Toxic except other Gliscor. You had to account for it's many other varying sets as well, mainly Swords Dance sets which could tear through teams. You also had other options like U-turn, Roost, Ice Fang for other Gliscor, Spikes, Knock off, and so on. Defensive checks were limited and offensive counter play needed you to put ice moves on any physical attacker that you could, and if it didn't have an ice move then it had to pressure Gliscor in some way, Kleavor was one of the best mon at doing this, being able to chunk it for around 37% if adamant, and nearly break through it if it was swords dance or banded. Obstagoon was also great at pressuring Gliscor with Bulk Up Guts sets which won the 1v1 against Gliscor. Despite this you still had no consistently riskless way to scout it's sets without getting caught off guard by another, and it restricted what could be viable offensively and even outclassing some of the ground types that would otherwise be healthy for the meta. On top of all this Gliscor enabled many of the stronger picks to be even more difficult to handle with Gliscor constantly pressuring every single mon on the opposing team. With how good Gliscor was it essentially influence the game into who could keep their own Gliscor alive for longer, with the first person to lose their's being at a potentially game ending disadvantage. And so on the 10'th of July Gliscor was quick banned by the 35 Council and was rerolled into Feraligatr.