Endermites glitch into blocks all the time and get stuck and jiggle about really violently and can't escape the block.
Also, for a while they aren't hostile after using a spawn egg.
Basically, pretty much everything about them, their movements, behaviour, AI etc. is broken.
MC-68043
Endermites Broken (Re-opened)
Resolved
Duplicate
0
Lefty Power123
(Unassigned)
Unconfirmed
Minecraft 14w34b
Retrieved
Well DUH of course it's a duplicate! Because I was told to re-open it in 68012 !!!!!!!!!!