Edit: i drank like three cups of coffee before writing this, and yes, i am insane.

Ive made a writing of all aftermaths of drinking the Grimace shake 

The shake itself always appears around the death scene, as palm/foot prints, slashes, vomit or salvia, splashes, on the ground, walls, the victim, mostly centered to the victim, or as a lead where the victim is.

-Torture. Grimace tortures the victim, usually in a forgotten place or basement, being tied up seems to be common. 
-Choking. Anything where the person chokes, of spits out the shake. Does include people vomiting large amounts if the shake even when they didnt consume a fraction of what comes out, and turning into the shake. May include rapid shaking.
-Beaten up. Pretty common, people may be seen lying on the ground, not moving.
-Going feral/crazy. After drinking the shake, people may start acting crazy, or like animals, posses abnormal powers (teleportation, clones, unreal events, hallucinations) and attack others, before eider choking on the shake, killing themselfs, or dying by Grimace. They might also immediatelly get addicted to it, and then go crazy.
-Drowning. In this case, people are left by Grimace in pools, rivers, lakes and such to drown after drinking it, or are drowned by him. Includes people dying next to rivers and such.

Choking mostly acts as a side effect: 

-Choking and Drowning, person may be seen flowing down a river while spiting/choking out the shake. 
-Choking and Beaten up, person may be seen on the floor/ground not moving, and then they spit/choke out the shake, but dont move more.
-Choking and Torture, person is tortured, and starts spiting/choking out the shake.
-Choking and Going crazy, person starts acting crazy/feral, and spits/chokes out the shake.

All the other can mix too: 

-Tortue and Going crazy, person is found tied up, laughing, or beaten up and acting like an animal.
-Drowning and Beaten up, person is found in a body of water with different wounds.
-Going crazy and Beaten up, person has hallucinations, or teleports, and then gets beaten up by Grimace.
-Torture and Drowning, person gets water boarded, or tortured and then thrown into a body of water.
-Beaten up and Torture, person gets tied or locked somewhere, where Grimace after a while kills them.
-Going crazy and Drowning, person drinks the shake, goes crazy, and then they drown themself or Grimace drowns them. 

All of these can happen with the addition of Choking: 

-Choking, Tortue and Going crazy, person is found tied up, laughing, or beaten up and acting like an animal, while spiting/choking out the shake.
-Choking, Drowning and Beaten up, person is found in a body of water with different wounds, while spiting/choking out the shake.
-Choking, Going crazy and Beaten up, person has hallucinations, or teleports, and then gets beaten up by Grimace, and then starts spiting/choking out the shake.
-Choking, Torture and Drowning, person gets water boarded, or tortured and then thrown into a body of water, where they start spiting/choking out the shake.
-Choking, Beaten up and Torture, person gets tied or locked somewhere, where they spit/choke out the shake, and Grimace after a while kills them.
-Choking, Going crazy and Drowning, person drinks the shake, goes crazy, start spiting/choking out the shake, and then they drown themself or Grimace drowns them. 

 (Got lazy on this one and mostly copy pasted it) 

 Now, Beaten up and Torture isnt the same. Beaten up is then the person dies near or on the place where he drank the shake, and Torture is then hes tied up, or tortured for a long time (Their death isnt quick).

 Ill be honest, some of those i havent yet saw, but there is a high possibility i will in near future

All of these lead to death at the end.

(Ive just spend a legit hour writng this for no reason at all
Maybe i did drink too much coffee-)