If you a command block that repeatedly "undo the actions of the mobs" then repeatedly do some actions on the mobs then the mobs will shake their head and their body (Sorry if your dirty minded). The actions are:

• Shear a sheep, a snow golem or a bogged ("/execute as @e[type=minecraft:sheep] run data merge entity @s {Sheared:0b}
  " or "/execute as @e[type=minecraft:snow_golem] run data merge entity @s {Pumpkin:1b}
  " or "/execute as @e[type=minecraft:bogged] run data merge entity @s {sheared:0b}")

• Put saddle on a pig, a strider ("/execute as @e[type=minecraft:pig/strider] run data merge entity @s {Saddle:0b}")

• Sit/Unsit your dog, cat or parrot ("/execute as @e[type=minecraft:wolf/cat/parrot] run data merge entity @s {Sitting:1b/0b}")

• Shear the wolf armor out of the dog ("/execute as @e[type=wolf] run data merge entity @s {body_armor_item:{id:"minecraft:wolf_armor"}}")

• Put a chest on a donkey, mule, llama or trader llama (/execute as @e[type=minecraft:donkey/mule/llama/trader_llama] run data merge entity @s {ChestedHorse:0b})

Some bugs like MC-274426, MC-274427 and MC-274450 make some more actions un-reproduce-able, those are.

• Naming/Renaming a mob using name tag
• Dye a sheep, a wolf collar or a cat collar
• Healing a iron golem using iron ingot
• Put saddle on horse, donkey, mule, camel
• Put wolf armor on a wolf
• Put carpet on llama or trader llama
• Cure a zombie villager using golden apple

STR:
1) Place down an repeating command block, right click on the command block, then type one of the above command, then set to "Always Active" and then click "Done".
2) Summon a mob that's compatible with the command
3) Get yourself an item that's compatible with the mob.
4) Make sure you're on creative mode.
5) Hold down right click or spam right click on the mobs while holding that item.

Observed result: The mob will shake their head and their body.
Expected result: The opposite of "Observed result".