How can I "disturb" my players?

Hi there, Midgardians!

So the other day I gave to a player a Potion of Poison and it was really fun to see their reaction. Now and then I use Mimics. 

What other things could I use to disturb my players a little bit?

Thanks in advance.

Animated Objects and furnitures ;

• Animated Armor
• Animated Flying Sword
• Animated Rug of Smothering

A lot of constructs have a feature where if they remain motionless, they appear inanimate.

You could always have petrified victims reanimate as Stone Cursed (MPMotM). 

It can really freak out your players if you start passing notes instead of responding out loud, but this only really works in person...

I sometimes make homebrew characters, so that could work , making some of your own. For example, draconic skeletons, giant spiders, etc.

Thank you for all your help! 

Spider-horse. I think the last edition they showed up in was AD&D 2E, so you'll have to homebrew a 5E/5.5E version.

Quote from CaptainJinxed >>

It can really freak out your players if you start passing notes instead of responding out loud, but this only really works in person...

Online, you could pull players into a private voice channel for about 15-30 seconds. Pretend to be looking for some notes, then apologize and then return to the regular channel. When the marks ask what you talked about, the player will only be able to say they weren't told anything. The marks won't believe them. You'd have to do a different thing if you pull a second player in of course.

Obvious fakeouts - blank notes, asides without content, etc. - are common suggestions for creating tension.  I think they’re terrible tools as they immediately have diminishing returns and ultimately are sacrificing one player, who, even if you say “don’t say anything” immediately knows (a) that particular tension item was meaningless and (b) not to trust when you do the same thing moving forward.  Ultimately, even if you throw in some legitimate asides also, it creates an atmosphere not of tension but of “eh. My DM is just screwing with us” that both harms the DM-player dynamic and very likely reduces player investment and therefore player tension.  Moreover, even when the session is done, this can have the lingering effect of ruining asides for everyone moving forward.

That is not to say asides and private information are not good ideas. They absolutely are - but you need to have some meat on them, and they should only be used sparingly.  After all, they’re a meta-level tool and rely on your players feeling more tense about the mystery than they would knowing the information itself.  Consider the two below circumstances.

1. As you walk into the room, you immediately notice the portrait above the mantle.  Four figures, stiffly posed in dark Victorian dress, their eyes the hollow lifelessness of portraiture. But it is their faces that draw your attention - for the faces are your own.

You could have done something like that through a perception check and a private aside with whoever passed the DC.  But that kind of atmospheric weirdness works best when the entire party receives the information at the same time, and can collectively sweat about what it might mean.

2. The lights flicker and you are plunged into magical darkness.  A cackling laughter seems to dance among you as you hear the scurrying of soft feet and the rush of a wind from a figure swiftly moving past.  The lights come back on, and the four of you are standing in the room.  Alone.  Can everyone please privately roll a charisma saving throw without telling the others?  *DM then chooses one player who failed the DC.  The DM then messages everyone… with all but the chosen one receiving “you are not the doppelgänger.  The last player is given instructions to try and blend in.*

Here, the mystery itself is the cause for suspense.  There is a tangible, mechanical reason information is being suppressed and the suppression is not merely a lazy tool to help build suspense, but the suspenseful element itself.

Some additional thoughts.  Because of how TTRPGs work, you do not necessarily have the timing pressure of a film or novel - players generally move at their own pace. Using a sand timer when in regular time (combat moves in slow time, so a timer is not necessarily the best place for this) is a great way to add suspense for in-person games, since it adds a visual element of time running out.  I am personally a fan of an escalating threat - instead of one timer leading to a bad thing, reusing the same timer and escalating… something that the players may or may not get omens about.

Lastly, the nature of TTRPGs is that a lot of it happens within a player’s mind.  And players are often much better at scaring themselves than the DM is going to be.  Cryptic messages and omens, various mildly offputting comments.  Let the players fill in the details themselves, will often be more suspenseful than you telling them something and expecting them to be scared by it.  The key to suspense is letting them build up a threat, then hit them with something at the right time.  “You walk into the room and are attacked by carrionettes” is far less suspenseful than “you walk into a room.  Shelves and shelves of porcelain dolls line the wall, their heads all turned as if to watch the entrance. *wait for a bit for the party to start overthinking the room, then privately ask one of them for a save and start combat, hopefully already having switched their soul.*