When a Tuber's Tube Tomb is unable to adequately seal a hull breach they may choose to self weld. This essentially liquefies Tube Tomb's outer shell then quickly hardens it again. The intention is to use the Tube Tomb itself to clog a hole. Larger holes can require multiple Tube Tombs to self weld in order to be properly sealed. Baking a Spud always kills the Tuber inside and it is seen as a noble sacrifice.