I did promise to follow up on which plant I would use to represent Venomous Tentacula in my miniature greenhouse. The plant is shown in several forms in the Harry Potter universe. As it is described in the Harry Potter wiki:
The Venomous Tentacula is a green, spiky, toothsome plant with mobile vines that try to grab living prey. Venomous Tentacula expels venom from its shoots, and its spikes are deadly. Its bite is highly poisonous and can prove fatal.
In the sixth Harry Potter book, the plant is discussed as one that lives in Greenhouse 3 and regularly tries to strangle students. In HP 6 (the movie) Professor Slughorn is shown snipping leaves of a Venomous Tentacula late at night, stealing them because they are so valuable. In that scene, the plant has dark green foliage which are not very distinctive except they are writhing.

I decided to use a plant whose appearance evokes the name Venomous Tentacula rather than trying to match the movie, trading cards, or games.

For my Venomous Tentacula I will use Senecio radican glauca, also known as “String of Bananas.” Doesn’t sound threatening but I have been growing long strands of them and will hang them from the ceiling of the greenhouse. They will live inside this cage which obviously they have broken out of!

I also need Devil’s Snare” which the Harry Potter wiki describes as,
” composed of a mass of soft, springy tendrils and vines that possess some sense of touch. This plant uses its creepers and tendrils to ensnare anyone who touches it, binding their arms and legs and eventually choking them.”
Devil’s Snare is encountered in HP1 (the movie) by Harry, Ron, and Hermione when they bypass the three-headed dog, Fluffy, and drop into a Devil’s Snare plant. on their way to finding the Philosopher’s Stone.

It is a dangerous plant owned by Professor Sprout and resides in Greenhouse 3.

I like this heart-shaped Dischidia ruscifolia because it looks to me like those pads could grab onto you and hold you tight.