Meganium has chronically been rated the worst starter mainly due to its type, stat distribution, and limited natural movepool.

Granted, grass types are relatively challenging to main, as the type has the most weaknesses , at five weaknesses, but where most other grass starters have some other aspect of their character to compensate, such as Sceptile's higher speed and range attacks, Venusaur's healthpool and dual typing, Serperior's hidden ability, as well as the signature moves of Chestnaught and Decidueye, Meganium has relatively little to offer.

Its has relatively high defenses and low speed, suggesting a defensive, damage-blocking style of gameplay, but this is negated by its typing and muliple weaknesses, Serperior's similarly higher defenses also seem to suggest the same style, but it has a stat-boosting hidden ability that allows it to be viably used in combat for the long term.

The only other grass starter who is worse than Meganium gameplay-wise, would be Torterra, who is similarly slow and defensive like Meganium, but has an added weakness of being an extremely vulnerable grass-ground type, with no other compensating aspects.

This is just a general consensus of the worst starter gameplay-wise.

(For worst starter in the anime, based on my opinion, it would most likely be Charizard. His disobedience has costed the protagonists several key battles as well as an attempt at the regional championship at one point, if I recall correctly.)

The fuck's wrong with Meganium?