In the file `src/p_user.c` a method is defined named `P_SpawnGhostMobj()` responsible, amongst other things, for producing the cloned ghostly `mobj_t` that follows a player sometimes during gameplay as a visual effect. The method is designed to deep-copy a large amount of one `mobj_t` into another then adjust the result from there to make the latter of the two `mobj_t` instances appear as a ghost. Below is a snippet example of how that is achieved throughout the implementation: ``` ghost->spritexscale = mobj->spritexscale; ghost->spriteyscale = mobj->spriteyscale; ghost->spritexoffset = mobj->spritexoffset; ghost->spriteyoffset = mobj->spriteyoffset; if (mobj->flags2 & MF2_OBJECTFLIP) ghost->flags |= MF2_OBJECTFLIP; if (!(mobj->flags & MF_DONTENCOREMAP)) ghost->flags &= ~MF_DONTENCOREMAP; ``` Most of this makes sense to me however the subject of this issue is this part in particular: ``` if (mobj->flags2 & MF2_OBJECTFLIP) ghost->flags |= MF2_OBJECTFLIP; ``` It's doesn't make sense to me from both observation of the rest of the source code and my understanding of bitwise operations to interact `MF2_` flag values with an `MF_` member like `flags`. Additionally, the member name that `MF2_` flags are intended to interact with, `flags2`, is only one character removed from the `flags` member. What I am suggesting is that `ghost->flags` is likely a typo and that the snippet above should instead read as the following: ``` if (mobj->flags2 & MF2_OBJECTFLIP) ghost->flags2 |= MF2_OBJECTFLIP; ``` I cannot (be bothered to) contrive a situation in-game in which this typo theory could be proven and I do not want to make a merge request resolving this "issue" until I can have it confirmed by the developers that my theory is correct, not to mention that it's such a tiny change that a merge request would be far slower than a member of the team themselves resolving this. Given all this, I put this issue ticket out to you the dev team to see what you think. Is it a typo? Is it intentional? Whatever the case, I feel glad to have made sure the occurrence went noticed.