there’s a lot of people asking for this so ill do a short guide on it
all you have to do is get a sentry and put a very small bucket in this exact spot
it works by blocking the sentry’s range point of origin (aka the spot the range originates from) thus it cant see anything and wont attack but can still be attacked
(its 
bc its such a precise spot)(I’ve only tested this on the default sentry not the green or pink plants so the point of origin might be different)
in depth steps of the newer dudes
part 1: the set up
step 1: place a sentry down
step 2: place any bucket down
step 3: shrink the bucket
part 2: the execution
step 4: move the bucket to this spot
step 5: test and slightly edit if it doesn’t work
step 6: once you get it in the right spot congrats you did it!
possible mistakes
miss 1: bucket doesn’t have collision
miss 2: bucket to small and/or in the wrong spot
miss 3: bucket is off on game start
how to make the bucket disappear when the sentry dies
step 1: place two wire relays
step 2: wire the sentry to both of the relays like this
relay sentry
relay ----- 
when knocked out
bucket relay
hide prop ----- relay
(note this only works if the sentry doesn’t respawn)
uses
a list of uses
- killable npc
- quest giver
- respawning prop
- triggerable guards
