Stasis Giant is a sub-boss found on the 180th floor of Tartarus in a group of three. They impede the player's progress and must be beaten to proceed. It later reappears as a normal enemy in the Harabah Block of Tartarus, between floors 202 to 213.
Try to bring any high level +Evade Slash shoes equipped with the Main Character and a Persona with both healing skills and multi-target Ice/Elec skills (Titania for example). Party can consist of anyone except Aigis, Junpei or Koromaru due to the boss resisting both Fire and Physical attacks. Your best bet would be to go with someone who has a healing skill of their own (Ken, Akihiko,Mitsuru and Yukari) and someone who has a multi-target Ice/Elec ability (Mitsuru and Akihiko). Chernobog is an incredibly useful Persona for this fight, because while he may not inherently have any particularly effective attacks against the Giants, he eventually learns Megido and his immunity to Slash damage can dramatically increase your survival odds, . Attack Mirrors are also very helpful for this fight, like they are in most melee-centric boss battles.
If you have shoes with high +Evade Slash and your party members were to be knocked unconcious, it is a lot safer to try and keep yourself alive by using healing skills and attacking while at full health rather than wasting a turn reviving them. It is even possible to solo this boss at a relatively high level using this tactic.
Persona 4
Stasis Giant appears in 6th and 7th Paradise of Heaven within the Midnight Channel. It will attack physically and cannot be dizzied. After being defeated, it may drop Prime Steel. Selling 4 Prime Steel will unlock the Kenka sword for the protagonist.