The plants aren't much larger than a house cat—think of a moderately sized philodendron with an ankle biting problem. They'll nibble and bite, but they won't do much harm. He'll easily be able to take one or two back, especially if he shields to protect himself.

Very dangerous. Widow's webs tend to control less than subtly manipulate. Your head might feel like its full of cotton, decision-making becomes difficult, and the Black Widow talking to you suddenly seems like an excellent source of information. You're welcome to play fast and loose with how easily Rhus' mind would be ensnared by a Black Widow's web whether by making it very hard to trap him or, once he's trapped, it's very easy for him to see through.

Black Widows are also excellent with poisons, and all of them have a venomous tooth under the ring finger of their right hand (thanks for being so extra, canon). Since he's a healer and he's smart, he's definitely noticed that Fayura has one.