Echidna flesh shifting

The tunnels that Coil had used to move his trucks in and out of the base had been collapsed, and it had been recent. She could smell the smoke from the explosives. She spat out a Vista, then another, and another, until she had one that could give her a way in, shrinking the rubble and expanding the corridor.

In her restlessness, unable to shake the idea that her sanity was slipping away moment by moment, she pushed her way through the last length of the rubble, absorbing it into herself and spitting it out behind her, moving through it as though she were a thick fluid; even her bones dissolved when needed. The only thing that slowed her down were the capes she'd stored within herself. Each of the three Undersiders, the tinker, and the girl in white. She used her strength to wedge gaps sufficient to squeeze the individual organs through.

- Interlude 18

The sticking point was Weld. Tattletale had apparently figured out that he was immune to Echidna's absorption ability, but he wouldn't be immune to her basic shapeshifting ability. She didn't have a lot of control over her form, or she surely would have chosen something without that number of legs, without the three mutant dog heads, but she did have the ability to shift her flesh around, and Weld was limited in how fast he could cut that flesh away.

[...]

There was a pause as her body heaved, my bugs could sense the movement as one of the bulkier dogs was repositioned inside her monstrous lower body, and then she puked up one of the dogs, along with a handful of humans.

- Scourge 19.1