spider/possessed AI jump speed bug

[quixilver87]

Steam or GOG

Steam

Single Player/Multiplayer

Single

Operating System

Windows 10

Terraria Version

1.4.0.3

Controls Used

Keyboard/Mouse

when a spider AI'd monster is falling, lands where there is a wall they can climb on, and then jumps the entity can gain insane speeds. wall creepers jumping 40 blocks high in my spider farm, recluse's seem to not be as harshly affected but I've also blocked off line of sight in that farm. the possessed forward movement speed seems to not have a cap as long as they can continue to jump after the first accelerated jump. after 1 accellerated jump and 1 regular jump they can jump over 100 blocks horizontally at faster than 80mph as read by the stopwatch.

 

[Leinfors]

This is a little difficult to visualize based on your description, is it possible to provide a video?

 

[CongratsIsTrash]

Oh yeah, I've seen this a lot with Blood Crawlers, basically, when they're in their fighter AI mode, and fall down and land on a block which has walls behind it, they start a jump while in the fighter AI for a couple frames before switching over to the spider AI mode, but it keeps the jump momentum when it switches to the spider AI mode, which causes them to fling themselves upwards on the wall.

 

[quixilver87]

I'll see if I can get a video of it, but the possessed example is easy to reproduce- just make a flat clearing, put up 3 blocks high of walls, and stand on a platform 20 blocks up.
the possessed will crawl to under you on the wall, try to crawl up the wall towards you, fall off because the walls end. when they land again they can randomly gain huge horizontal speed, seemingly when they jump, transition to the wall, and fall off the wall again due to the increased momentum.

the spiders are more difficult to replicate- But it still seems to be linked to crawling off the top of a wall, falling, landing,a jump and a transition to crawling on the back wall with the momentum of the jump and no gravity effect. maybe a simple fix would be to reset momentum when transitioning from walking to wall-crawling.

 

[Metoot]

Bumping with video evidence.
Here we can observe two Posessed flinging themselves around, one being able to fling itself out of a house.

Edit: quickly went back and added a ruler, should be helpful in some way. Adds up with the report of standing 20 blocks up, though the posessed spend more time flinging around on the furniture.

Spoiler: Screenshot

Edit 2: The distance is not even relevant. Being above The Posessed and it not being able to reach you is enough.
Edit 3: Not even sure being above is necessary. Maybe furniture in front of walls is enough? I don't have the tools to verify that as a mere player, but I can at least confirm that this is a bug that exists.