An immediate pick-up is an item that provides some benefit the instant it is picked up, but can't be saved for later. What are your favorites?

My personal favorite is the Vitamin X item in StarTropics. When picked up, it restores your health to the maximum of 22 hearts, *even if that means exceeding your maximum*. When you first find it, you have 16 heart containers, so you end up with 22 out of 16 hearts after picking it up. Of course, while your health is above the normal maximum, you gradually lose health, but it is still one of my favorite immediate pick-up items in any video game I've played.

What are yours?

Soulsphere from Doom
Quad Damage from Quake

The chainsaw from Doom II is the first one that comes to mind.

Anything that makes you do extremely high damage: Quad damage from Quake, that tea thing from Alice and God Mode in RoTT.

RoTT had some funny ones like Shroom mode and Elasto mode that we found really amusing when I played the game with my friends after it first came out. Revisiting the game after years though, they were more annoying than anything.

Hookers.

Giant purple dildo.