Skull Tee is an inexpensive item that can be bought from the cheap items section in Nook's Cranny. You can also find it inside the balloons.
You can't craft Skull Tee but you can buy it from the sellers below.
Source notes: Available from either Mable's temporary shop or Able Sisters shop
|Craftable: No||Customizable: n/a||Catalog: Yes|
|Source: Able Sisters||Size: 1x1||HHA Series:|