That’s actually not correct. It’s “activated” by default, i.e. it likes to eat flesh. The radioactive stuff is just used to make it grow so it can (and will) eat bigger things.
You can “deactivate” it in both states. @DZ-Jay you should play Maniac Mansion!
Yes, my bad. I misanalyzed the effects of the radioactive waste.
I have not understood this, though. Which “both states”?
I did play it, I just never finished it. I’ll have to play it again. 
I think it means while the plant is big and small.
Hmm… Then I’m probably missing something. @Nor_Treblig: what does it mean that you can deactivate the plant when it’s small? Are you talking about TWP, about MM or about both games?
That reminds me I encountered a dead end in Maniac Mansion when I
fed the plant Pepsi and radioactive water but in the wrong order. Then there’s no way to climb up into the attic.
Depends on the version, but I also think I´ve encountered versions of the game that have a bug where the plant burps but the character still says “it bit me” when trying to climb up.
I also discovered that sometimes the telescope doesn´t register all of the coins. it disappears from the inventory, but it doesn´t make a sound and you can´t push the button. That means you don´t have the freedom to waste a single coin. Move it once in the false direction and you can forget about it.
In both games you can feed the plant a fizzy drink and it will start burping and stop eating. That’s what I meant with “deactivate”. You can’t reactivate it though.
Yes, apparently you have to feed the plant the contaminated water instead of just watering it, so this won’t work anymore if you feed it Pepsi first.
(appreciating these spoiler blurs as I’m currently on that exact bit in MM 
)
OK, I fixed the entry in the first post list. Thanks!
To a moderator:
Is there a way to get edit privileges to the first post again? I would like to add more entries to the Easter Egg list so that it is comprehensive.
Thanks,
dZ.
I would like to jump in: It would be great if I could edit the first post of the version thread. (@RonGilbert, @eviltrout).
btw: Who is a moderator?
You should post your discoveries or corrections in the thread if you have any, then I can add them to the first post once I gain access. I just haven’t updated the thread in so long that I lost access to edit.
dZ.
You should make (have made) such kind of posts a Wiki post (after creation click on the gear symbol).
I’m sure then they can be edited even later, and also by other people to complete information.
I hope our moderators can convert those posts even now.
Well, now I can:
it was a reference to some things you can find: they are round and shiny, and they are hidden deeply somewhere…
By default posts can only be edited for 60 days after they were made.
I could make it a wiki post for you, but that way any trust user could edit it.
But that´s why we´re called “trust users”, we wouldn´t do that if it would bother him.
But eviltrout can also modify some things.
Hmm… I was curating the list myself, writing all entries. This is why I didn’t turn it into a wiki back then.
I rather keep it that way. If you cannot grant edit access to me, then someone else can create a separate wiki for their own purposes if they like, in their own format and style.
dZ.
@eviltrout is hidden in that “System” thing 