WHATSIS
doodad, doohickey, doojigger, gimmick, gizmo, gismo, gubbins, thingamabob, thingumabob, thingmabob, thingamajig, thingumajig, thingmajig, thingummy, whatchamacallit, whatchamacallum, whatsis, widget
(noun) something unspecified whose name is either forgotten or not known; “she eased the ball-shaped doodad back into its socket”; “there may be some great new gizmo around the corner that you will want to use”
Source: WordNet® 3.1
Etymology
From what's this or similar.
Noun
whatsis (plural whatsises)
Any object whose actual name one does not know or cannot remember.
Synonyms
• See also thingy
Anagrams
• saw shit
Source: Wiktionary