TIL: If you intend to catch something, and you're using a pal that can freeze, do not use a rocket launcher on the target when it is frozen. I went after Paldius and Necromus and my Lyleen Noct froze them, then I fired a rocket. Necromus took a hit, and Paldius' nameplate disappeared. The next time I saw his nameplate, it was for a split second followed by "first boss kill". Turns out that while frozen, Pald got sent to the atmosphere then returned nearby as a mushy paste on the ground. Easy kill... but I wanted to catch it.