Venusaur

Mega Venusaur is a decent defensive check to a number of prominent offensive Pokemon in the tier, such as Mega Mawile, Serperior, Tapu Koko, and Kartana lacking Normalium Z. Thick Fat separates Mega Venusaur from other defensive Grass-types like Tangrowth and Ferrothorn, as it isn't immediately forced out by Ice- and Fire-types like Heatran, Kyurem, and Weavile. However, that's where Mega Venusaur's strengths end. Mega Venusaur's lack of consistent long term recovery, extreme four-moveslot syndrome, and susceptibility to entry hazards accentuate how easy it is to wear down quickly. Other defensive Grass-types such as Ferrothorn and Tangrowth both provide more for teams and are much more consistent in the long run. Tangrowth's Regenerator makes it less burdened by entry hazards and gives it more longevity than Mega Venusaur, while its better typing and freedom in its moveslots allow it to dually check Ground-types and also fit utility moves such as Sleep Powder, Stun Spore, and Knock Off more easily. Ferrothorn also has a myriad of utility options such as Spikes, Stealth Rock, Thunder Wave, and Knock Off which it can easily fit while also utilizing its Steel typing to better check threats such as Tapu Lele and Mega Tyranitar. Mega Venusaur struggles to shine offensively with such tough competition from Kartana and Serperior; its low Speed and lack of threatening presence hold it back even further. All of these Pokemon can also hold an item to assist them in either defensively checking or offensively threatening foes, making Mega Venusaur generally a worse choice on a team compared to its competition.