I think you are going for cactus, any of several kinds of spiky desert plant. You can use either cacti or cactuses as the plural form.
The plural of "bus" is "buses."
The plural form of Jones is spelled "Joneses".
The plural form of "halo" is spelled "halos."
The plural form of donkey is spelled as "donkeys."
The plural form of the name "Wu" is spelled as "Wus."
The plural form of "axe" is "axes."
The plural form of the noun company is spelled companies.
The plural of "bus" is "buses."
The plural form of Jones is spelled "Joneses".
The plural form of "halo" is spelled "halos."
The plural form of donkey is spelled as "donkeys."
No, crisis is the singular form; the plural form is crises.
The plural form of "philosophy" is spelled "philosophies."
The noun form for the number 40 is spelled forty. The plural form is forties.
Pictures
Elliptical is an adjective. English adjectives have no plural form.
The plural form of the name "Wu" is spelled as "Wus."