Venusaur

Poison

With an excellent defensive typing and two decent forms of recovery, Mega Venusaur is an amazing defensive stop to many offensive and defensive foes alike, ranging from Celesteela to Greninja to Tapu Koko. Thick Fat is a wonderful ability for Mega Venusaur, as it halves the damage taken from Fire- and Ice-type moves and makes it a better wall as a result. Mega Venusaur's secondary Grass typing is essential for Poison teams, as it can reliably check problematic Ground-types such as Dugtrio, Hippowdon, and Mega Swampert through Giga Drain. However, like many defensive tanks, Mega Venusaur is rather slow and susceptible to faster offensive threats in Dragonite and stallbreaker Hydreigon. Also, although Mega Venusaur is meant to tank many hits, it can be worn down by chip damage from entry hazards and moves upon switching in. This is because its main recovery in Synthesis only has 8 PP, while its other option in Leech Seed only heals a small amount of health each turn and has a chance to miss the foe.

Grass

Mega Venusaur is a staple of Grass teams because of its excellent typing, offenses, and movepool with superbly balanced stats. A Grass / Poison typing and Thick Fat grant Mega Venusaur valuable neutralities to Fire-, Ice-, Bug-, and Poison-type attacks. Between this defensive utility, Synthesis, and tremendous mixed defenses, Mega Venusaur serves as a formidable sponge for both physical and special attacks and a sturdy check for threats such as Nidoking and Mega Scizor. With great offensive stats, Mega Venusaur serves the defensive core without being passive enough to take advantage of. However, Mega Venusaur relies on Synthesis for reliable recovery, which has a mere 8 PP. Thus, Mega Venusaur is susceptible to being worn down by entry hazards and chip damage and cannot take repeated hits from potent wallbreakers such as Landorus and Mega Charizard Y. Furthermore, while Poison typing offers a valuable neutrality to Poison- and Bug-type moves, it also opens up a weakness to Psychic-type attacks and makes it difficult for Mega Venusaur to manage powerful Ground-type threats such as Diggersby and Excadrill.