- For other uses, see portal.
In Plants vs. Zombies 2, portals are the main environment modifiers of Modern Day. They appear on any tile of the lawn and spawn special zombies from the respective world they are showing. The placement and the zombies spawned are fixed and never change. There is never any indication on whether they are going to appear on a level, nor the zombies they will spawn.
If a plant is planted on the tile on the left of where the portal appears, it will be bounced to a free tile on the lawn. An instant-use plant and tombstones can prevent a portal from appearing if placed where the portal is supposed to appear a little before they show up. However, this relies on timing.
Portals are deployed at half of the player's lawn. On this note, the portal will stay and summon a zombie, based on its corresponding world. When a zombie arrives via portal, it appears in a same way as how Dr. Zomboss summons zombies using his first four Zombots. Furthermore, their appearance is limited and will close after a definite period of time.
In Highway to the Danger Room, the behavior is further observed. On levels 1-10, only a single portal from each world will be opened and will mostly summon one zombie, ocassionaly it may spawn three random zombies. On levels 11-20, two random portals will appear and two random zombies will be summoned. From this level onwards, portals will appear very frequently and will behave erratically and can have portals of same type appear. For example, there can be three Jurassic portals appearing and can deploy Jurassic Imp, Jurassic Bully, or Jurassic Fossilhead at once. At levels 31-40, three portals will appear and their durations are extended. As the player goes higher and higher, the number of portals appearing increases, the duration of portals opening also increases, as well as summoning up to three powerful zombies representing each world.
Portals in certain Piñata Parties may sometimes summon different zombies, depending on their current level appearance. The zombies summoned are programmed specifically by party.
Far Future: Piñata Party
Highway to the Danger Room/Inzanity Levels
Other known combinations
Modern Day levels
Portals are with no doubt a very hard gimmick to deal with. They can easily spawn the most hard to defeat zombies into the heart of your defenses, like MC Zom-Bs and Surfer Zombies, so the best counter for them are Chard Guards and Hurrikales to instantly push them backwards.
On the other hand, it can be easy to prepare for the upcoming zombies, as the set that comes out never changes, but they do appear in a random order. Ready your Blover if a level has a Pirate Seas portal. Immediately place area of effect plants once a Dark Ages portal appears. Use E.M.Peach for the Far Future portal. Another strategy is to place a Celery Stalker behind the portal, as it will attack zombies that spawn from the portal for heavy damage without the threat of retribution from them.
Highway to the Danger Room
Portals here are worse than in Modern Day levels, as the portals can now summon more dangerous zombies like Chicken Wrangler Zombies, Boombox Zombies, and Wizard Zombies. Because one cannot retry a level, only one can guess if a portal type will appear in a level and bring certain plants to hope for the best that the portal will appear, else a seed slot is wasted. Later in the Endless Zone, more dangerous zombies will be spawned, and the portal density will greatly increase to the point that portals can be stacked on top of others.