Items ruining run to the beast?

[pop pop]

So far I know that ipecac is unusable in the final fight
Flat stone also complicates harbinger fights, although on the beast itself is doable
What are other items you would advice against taking for the home runs?

[Saturnine]

I found that any item that involves spawning friendly flies or spiders doesnt work too well. They all just fall down to the bottom where the lava is and get stuck there.

[HeraldOfOpera]

Censer and Night Light both make the Beast's only real attack unavoidable, but she probably won't get to use it more than once so it isn't the complete run-killer people say it is.

[F IAaP n]

Flat Stone.
If you get Potato Peeler, better not spend more than 2 red heart containers, since the Meat Boy would just spend the whole fight in the lava.

[steven]

Tisagion and homing tears. If you spam a little bit too much, your game crash coz the tears stays on screen for ever
Every familiar that run on floors (and not levitate around the player) just stucks in lava

[Menez]

Hemolacria
Ipecac
Dr. Fetus

[Marfolog]

Knockout drops with high luck really messes up the beast (can be useful still). Spirit sword is also really bad because of all the stalactites, you will get knocked up and down while trying to hit the beast.

[qlipox]

Oculus Rift - had in on lost run and it was horrible against Ultra horsemen

[Krakkip]

Isaac's Heart make dodging the stalactites impossible. Only barely won with just one health left in my tainted Maggie run.

[restore]

I would say that ludovico is quite useless as it reset itself constantly, also with tainted isaac it kept crashing the game :D