@Jazzy_Butts Transporters have a memory, or buffer for storing sent beams. Since they work by breaking the matter down into energy, and then reassembling it later, it can be stored pretty much indefinitely. You might need to keep the transporter powered or risk it disappearing forever. So transporting something into something else isn't really a problem with later transporters. They also have a shield to keep debris and weapons fire and whatnot from affecting the transportee.

@Jazzy_Butts That shield should limit the size of objects to be smaller than the shield, and by extension smaller than the ship the transporter was on. But both of those were safety features that had to be added, so with the earlier ones, those things definitely happened. Don't know about the second one, but stuff actually did get transported inside someone. Oh, and most safety features in Star Trek can be overridden with either clearance or tech knowhow. So if you wanted to cause it, you could.

@Sudodeme Ok so I'm watching TNG Encounter at Farpoint part 2 and when Wesley falls into the water in the holodeck he comes out of the holodeck and says to picard who just showed up "I'll get a towel to mop this water up" (or something like that) but if it's holographic water shouldn't it have vanished the moment it left the holodeck???

@Jazzy_Butts Now, if you want an explanation, the holodeck might use small amounts of actual liquid to get the feeling of being wet right, but if you want something to think/laugh about, exploit that shit like a video game for free resources. Just teleport things out of the holodeck to spawn them like creative mode.

@Sudodeme I'll give them a pass and say that everyone in the scene knew the water was about to dematerialize shortly, but Wesley thought it would be funny to make a stupid joke about needing a towel (lol jk Captain Picard, on account of it being holographic water hurr hurr, "Shut up Wesley")