Flash Foliage

Flash Foliage can be cast only during an opponent's combat phase, after attackers have been declared. If it's cast after combat damage is dealt, the Saproling will enter blocking the attacking creature, but will neither deal combat damage to it nor be dealt combat damage by it.

The Saproling token is blocking the attacking creature, even if the block couldn't legally be declared (for example, if the attacking creature has flying, or is Vindictive Mob).

Putting a blocking creature onto the battlefield doesn't trigger "When this creature blocks" abilities. It also won't check blocking restrictions, costs, or requirements.