Giant wood moths (Endoxyla cinereus

The larvae of these supersized insects, known commonly as witchetty grubs, burrow inside eucalyptus trees before reemerging around a year later as caterpillars that then use silky threads to lower themselves to the ground, where they feed on the tree's roots. The caterpillars then undergo a staggering metamorphosis and emerge in their gigantic final form, according to the Australian Museum.