By experience, a maximum edit distance of 6 gave good results
It does read Mythic, even if it will likely be one of the cheaper Mythics
But you can only counter renew with anything that counters abilities
From the official rules: 616.1
Evil Armor Class 22 (natural armor) Hit Points 364 (26d10 +182) Speed 50ft Saving Throws Strength +16, Constitution +14 Skills Athletics +16, Intimidation +10, Survival +13 Damage Resistances non-magical Bludgeoning, Piercing and Slashing Damage Immunities Fire, Lightning Condition Immunities Frightened, Blinded Senses 120ft Darkvision, 30ft Blindsight Languages Behemoth Challenge 21 The Behemoth can cast any of the following spell requiring no material components, Wisdom is his spellcasting modifier for these spells (Atk bonus +13, DC 21)