Big Piranha Plants are, obviously, enlarged versions of the Piranha Plant. Due to their size, they chomp slower with a low-pitched bite sound.
Big Piranha Plants act exactly like grounded Piranha Plants, but with a bigger hitbox. They'll simply stay in one place, and can be killed by multiple fireballs or a singular Hammer. They'll break out if they're hit by an iceball.
Big Piranha Plants appear once again in Newer Super Mario Bros. DS, where they're still uncommon enemies. They'll first be seen in Everbrown Meadow, with their last appearance being in Cloudbolt Chasm.
Big Piranha Plants, once again, are just enlarged Piranha Plants. They have a slower chomp and low-pitched bite sound.
Once again, Big Piranha Plants are just grounded Piranha Plants with a bigger hitbox. They only difference being, once again, that they'll die with three fireballs instead of one.