Most monster manuals have stat blocks for giant versions of normal

Fought a giant gecko when it was the mount for a goblin king

Remember when people did not ask stupid questions that any amount of thought could have dismissed?

>>50685708
>Where do all of those giant animals come from
Wizards make them.

>>50685708
Either what >>50688396 said or some combination of magic and/or natural factors allow them to live. There used to be millipedes the size of cars, but there's not enough oxygen in the air for them to survive anymore.

Alternatively, you could not think about it

>>50685708
>how often do you actually fight, for example, a giant gecko?
As often as the DM wills it.

File: gecko-side.jpg (13KB, 317x522px) Image search: [Google]

13KB, 317x522px

>>50685708
As often as he tries to sell me dungeon insurance, anon.

>>50688905
My players are building a dungeon to store their monster menagerie, so I'm gonna have to steal this idea now.

>>50685708
>wizards made them (on purpose or by accident)
>they evolved that way to compete with magical wildlife
>they were blessed by forest spirits/gods of nature to protect the forest

In any case, giant animals are decent as monsters. Nature's scary.

File: buh gok.jpg (60KB, 500x375px) Image search: [Google]

60KB, 500x375px

>>50685708
>how often do you actually fight, for example, a giant gecko?

As often as you encounter them. Don't you know that when animals grow to larger than their normal size, even if it is only slightly larger, they immediately are infused with an irrational and suicidal hatred of humans? It doesn't matter if you're way bigger and obviously stronger than them, if you're totally alien to their environment, or if they are not even predatory by nature. If they see you, they will come at you with the rage of a thousand suns and thrash wildly until one of you dies. Something to do with the brain expanding in size and making them retarded, I think.

>>50688794
>There used to be millipedes the size of cars
>https://en.wikipedia.org/wiki/Arthropleura
>up to 7.5' long
not quite, but still massive.