Knuckles the Echidna, one of these echidnas and a main character from the Sonic games.

Echidna, one of the characters in The Bouncer

The echidnas or spiny anteaters, a family of Australasian monotremes.

Echidna, a monster in Greek mythology.

(42355) Typhon I Echidna, the natural satellite of the asteroid 42355 Typhon.

Echidna (genus), a genus of moray eels.

Echidne, a junior synonym of Bitis, a genus of African vipers.

ECHIDNA - High Resolution Powder Diffractometer, a neutron diffractometer at Australia's research reactor, OPAL.

Echidnas (Sonic the Hedgehog), fictional anthropomorphic echidnas from the Sonic the Hedgehog series of video games.