Stomping Tantrum is a 75 BP Ground-type contact move that doubles in BP from 75 -> 150 if "the user's previous move has failed". This basically amounts to whether or not the attack animated (if it animated, it does NOT get the boost). These are situations I have personally tested (not exhaustive):
Situations that DO cause Stomping Tantrum to receive its 2x power boost:
-Previous attack displayed "But it failed!"
-User was flinched / fully paralyzed / hit itself in confusion
-User attempted to wake up from sleep / unthaw on the previous turn
-User missed its previous attack (<opponent> avoided the attack!). NOTE: If spread move, the attack must miss ALL targets.
-Previous attack was immune due to typing or Ability (e.g. Ground move into Flying-type or Levitate, Fire move into Flash Fire)
-Previous attack was ineffective due to a Terrain (e.g. priority move in Psychic Terrain, Spore in Misty Terrain would double ST)
-Taunt / Disable, etc. preventing the successful use of the user's previous attack
-Using Substitute while the user already has a Substitute
-Using Substitute while the user does not have enough HP to make a Substitute
-Using a boosting move while at +6
-Using a move like Recover while the user's HP is full or Heal Pulse while the target's HP is full
-Using a Z-move into an immunity
-Using a status Z-move whose final effect failed
-Move blocked by Primal weather
-Move failed due to lack of target (attacking an empty partner slot, all opponent's Pokemon fainted before the move was used)
-Instructing a Stomping Tantrum when the Stomping Tantrum user's move failed on the PREVIOUS turn (both ST are doubled)
Situations that DO NOT cause Stomping Tantrum to receive its 2x power boost:
-Previous attack landed into Protect, Wide Guard
-Missing ONE target of a spread move
-Follow Me / Rage Powder redirecting the Stomping Tantrum user's previous move
-Using Splash, etc.
-Breaking a Substitute / Disguise
-Sky Drop picking up the Stomping Tantrum user on the turn prior
-Sky Drop preventing the successful use of a move while in the semi-invulnerable state
-User is in recharge state (e.g. from Hyper Beam)
-Z-Stomping Tantrum never receives a boost; it is fixed at 140 BP.
-Sky Drop failing to pick up a Pokemon that weighs 200+ kg (this is an exception to the animation rule).
-Using Stomping Tantrum after Instructing a move to fail on the CURRENT turn (e.g. Instructing Protect, Protect fails, Stomping Tantrum has 75 BP)
If a spread move interacts with one slot having used Protect and the other slot meeting the Stomping Tantrum fail condition, Stomping Tantrum WILL double. Necessarily, this must occur AFTER Protect would block the move in the checks done prior to move success (see here: https://www.smogon.com/forums/threads/ultra-sun-ultra-moon-battle-mechanics-research-read-post-2.3620030/post-8096570).