MCPE-47518Sometimes Mobs Will Not Take Damage On Magma Blocks
Occasionally, mobs that spawn on, or land on magma blocks, will not take any damage from them. This is a rare occurrence, but can be easily spotted by having a raid spawn on magma blocks.
Mobs that are not taking damage on magma, will not pathfind or ever move. But as soon as they do move(or get moved somehow) then they will start properly taking damage.
Below you can see an image of a raid having spawned on a magma block platform, none of these guys are moving around, and now will take damage/die until they are moved. You can also see a baby drowned, that spawned on a magma block not taking any damage.
This bug hurts mob farms, and kinda breaks the practical uses of magma blocks, since they have one job. To deal damage to things.
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Sometimes Mobs Will Not Take Damage On Magma Blocks
Occasionally, mobs that spawn on, or land on magma blocks, will not take any damage from them. This is a rare occurrence, but can be easily spotted by having a raid spawn on magma blocks.
Mobs that are not taking damage on magma, will not pathfind or ever move. But as soon as they do move(or get moved somehow) then they will start properly taking damage.
Below you can see an image of a raid having spawned on a magma block platform, none of these guys are moving around, and now will take damage/die until they are moved. You can also see a baby drowned, that spawned on a magma block not taking any damage.
This bug hurts mob farms, and kinda breaks the practical uses of magma blocks, since they have one job. To deal damage to things.
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What this bug basically allows for, is passive mobs to spawn on none grass blocks, such as stone, concrete, beacons, iron blocks etc etc. The only thing the game is really taking into account for where to spawn things, is biome. This also affects some hostile mobs too(like raids)
So for instance, in super flat savanna world, with only stone platforms, you can have llamas spawn. As another example, polar bears can spawn on stone in snowy biomes. As you can see from these couple examples, the block check mobs should be doing is clearly missing in recent updates.
Things like cats(from villages), llamas, horses, rabbits, polar bears, and turtles can spawn on any block, as long as its in the correct biome and correct light level. Llamas (only in savanna biomes?) and rabbits, can also spawn under ground. They should be surface spawns only. Cats also spawn inside blocks.
Most of this bug was fixed in 1.10, passive animals needed grass to spawn, drowns needed water, and so did guardians. Now in 1.11 passive animal spawning is broken again. But the drown/guardian fix persists.
This also affects raids. Raids don't do any form of block check, at all. If you can stand on it, they will spawn on. They will even spawn under ground, which is a massive issue.
Below you can see images of these bugs in action, most of which where taken in a super flat testing world, so condense spawns into one area. Oh, and the raids are not taking damage on magma, due to this related issue: MCPE-47518
You can see a full demonstration and description in this video: https://youtu.be/ymgbqpCAOMQ
silentwisperer: I agree, and I use custom flat worlds and third-party editors myself when testing. But they can be misleading sometimes, so checking in vanilla is important.
I've reviewed the issues you mention in the updated description and your video that supports them to make a comprehensive list of the issues that still need attention, so that we can attempt to group them into bug reports appropriately. I see them as falling into the following groups:
- Mobs spawning on blocks that they shouldn't spawn on. This includes llamas spawning on cobblestone; llamas and horses spawning on stone; llamas, rabbits, and polar bears spawning on snow layers above stone; and turtles, polar bears, and rabbits spawning on stone-type blocks placed above frozen oceans. In the description you also said that cats spawn "on any block", but the video doesn't show that. I think it was an over-generalization, but see #3 below for the issue specific to cats.
- Mobs spawning underground. This includes llamas, horses, and rabbits spawning below stone. There's a complication here from the issue I discussed above in this reply to Eyeth, and which is being tracked at
MCPE-41273. Some of your test setups actually produce surface spawns instead of cave spawns,, but there wasn't enough evidence in the video to show that this was true in all cases, so we'll have to see if we can reproduce it as true cave spawns. - Cats spawning inside blocks. This is already being tracked at
MCPE-44442. - Raids not doing block checks. CornerHard confirmed this but didn't indicate whether it was intentional or a bug. We would like to have a new ticket for this, because spawning a raid is quite different from spawning a single mob or pack and the suppression of block checks could very well be intentional (though it might need some tweaking).
- Raids spawning underground. This is already being tracked at MCPE-45183. The issue with surface spawns that occur underground could also be at work here.
I'm omitting the issue of raids not taking damage on magma blocks, because you already reported that separately at MCPE-47518.
So as I see it, we would like to have a ticket created for each of numbers 1, 2, and 4.
Thank you for your report!
We're already tracking this issue at MCPE-47518, so I will resolve and link this ticket as a duplicate.
If you would like to add a vote and any extra information to the main ticket it would be appreciated.
If you haven't already, you might like to make use of the search feature to see if the issue has already been mentioned.
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Leo28456 They don’t take damage because there was another bug, that caused mobs to not take damage from magma blocks, which has already been fixed. See MCPE-47518
Can confirm in 1.11.4
Does this also apply to campfires if it's possibly?
Not sure, have not tested, would need further research:3
@silentwisperer I just asked that because campfires also have that feature where if you step on it it damages similar to this bug
Affects 1.13.0.18, can be solved by putting carpet on top of the magma blocks
yeah I remember when I finished a skeleton farm in my world and after a while I thought it stopped working but it was this bug that was preventing the skeletons from dying. (although when more skeletons fell down the others got pushed and took damage) I switched my farm from using magma blocks to using a trident killer because of this (and because trident killers kill much faster)
I have also been experiencing this problem while making an iron golem farm, where the village spawns cats which drop into a water stream and fall onto magma blocks. None of the cats die, adult or kitten, until they are nudged by the player or other entity. They also appear to loose some of their ai and can no longer path-find. This also works on camp fires and wither roses. edit: never mind after further testing the carpets do not give consistent results.
And I can confirm that carpets fix both the damage and path finding problems.This can be readily replicated with a system similar to the second picture spawning multiple cats specifically. (v 1.14.60).
Resolving issues that were marked as fixed in the 1.15 and 1.16 Betas, now that 1.16.0 is being released.